CVOICE :: Gateways Trunks and Signaling :: Pa...


Table of Contents
Course Files
  • 1 Introduction and Agenda Closed Caption 0h 14m
    2 CVOICE :: Gateways Trunks and Signaling :: Part 1 :: Theory Closed Caption 1h 04m
    3 CVOICE :: Gateways Trunks and Signaling :: Part 2 Closed Caption 0h 59m
    4 CVOICE :: Gateways Trunks and Signaling :: Part 3 Closed Caption 1h 05m
    5 CVOICE :: Gateways Trunks and Signaling :: Part 4 Closed Caption 0h 46m
    6 CVOICE :: Gateways Trunks and Signaling :: Part 5 Closed Caption 0h 56m
    7 CVOICE :: Gateways Trunks and Signaling :: Part 6 Closed Caption 1h 13m
    8 CVOICE :: Gateways Trunks and Signaling :: Part 7 :: Fax and Modem Closed Caption 0h 15m
    9 CVOICE :: UCME Basic Setup and Phone Registration Closed Caption 1h 07m
    10 CVOICE :: Dial Plan :: Planning and Design Closed Caption 0h 55m
    11 CVOICE :: Dial Plan :: Applied in UCME Closed Caption 1h 19m
    12 CVOICE :: Dial Plan :: Applied in UCME :: Part 2 :: Outbound Closed Caption 1h 06m
    13 CVOICE :: Dial Plan :: Applied in UCME :: Part 3 :: Site-to-Site VoIP Closed Caption 0h 53m
    14 CVOICE :: Dial Plan :: Applied in UCME :: Part 4 :: Site-to-Site VoIP SIP Closed Caption 0h 49m
    15 CVOICE :: Dial Plan :: Applied in UCME :: Part 5 :: Site-to-Site VoIP TrunkGroups and COR Closed Caption 0h 50m
    16 CVOICE :: H.323 Gatekeepers :: Part 1 :: Theory Closed Caption 1h 16m
    17 CVOICE :: H.323 Gatekeepers :: Part 2 :: Demo Closed Caption 0h 22m
    18 CVOICE :: H.323 Gatekeepers :: Part 3 :: Demo Closed Caption 0h 45m
    19 CVOICE :: Cisco Unified Border Element :: Theory and Demo Closed Caption 0h 57m
    20 CVOICE :: Quality of Service :: QoS Theory :: Part 1 Closed Caption 0h 49m
    21 CVOICE :: Quality of Service :: QoS Theory :: Part 2 Closed Caption 1h 26m
    22 CVOICE :: Quality of Service :: QoS WAN Demo Closed Caption 1h 13m
    23 CVOICE :: Quality of Service :: QoS WAN Demo :: Part 2 :: Link-Specific Closed Caption 0h 57m
    24 CIPT1 :: Architecture Overview Closed Caption 1h 08m
    25 CIPT1 :: Provisioning Basic Setup Closed Caption 0h 53m
    26 CIPT1 :: Media Resources :: Theory Closed Caption 0h 38m
    27 CIPT1 :: Media Resources and Features :: Demo Part 1 Closed Caption 1h 29m
    28 CIPT1 :: Media Resources and Features :: Demo Part 2 Closed Caption 0h 58m
    29 CIPT1 :: PSTN Gateways and Trunks Closed Caption 1h 27m
    30 CIPT1 :: Dial Plan Fundamental Concepts :: Part 1 Closed Caption 1h 03m
    31 CIPT1 :: Dial Plan Fundamental Concepts :: Part 2 Closed Caption 0h 37m
    32 CIPT1 :: Dial Plan Fundamental Concepts :: Part 3 Closed Caption 0h 42m
    33 CIPT1 :: Dial Plan Fundamental Concepts :: Part 4 Closed Caption 0h 37m
    34 CIPT1 :: Dial Plan Fundamental :: Demo Part 1 Closed Caption 1h 00m
    35 CIPT1 :: Dial Plan Fundamental :: Demo Part 2 Closed Caption 0h 37m
    36 CIPT1 :: Dial Plan Fundamental :: Demo Part 3 Closed Caption 1h 03m
    37 CIPT1 :: Native UCM Presence Closed Caption 0h 26m
    38 CIPT1 :: Unified Mobility :: Part 1 Closed Caption 0h 19m
    39 CIPT1 :: Unified Mobility :: Part 2 Closed Caption 1h 07m
    40 CIPT1 :: Mobile Voice Access Closed Caption 0h 37m
    41 CIPT2 :: Issues with Multisite Deployments Closed Caption 1h 12m
    42 CIPT2 :: Issues with Multisite Deployments :: Demo 1 Closed Caption 0h 51m
    43 CIPT2 :: Issues with Multisite Deployments :: Demo 2 Closed Caption 0h 58m
    44 CIPT2 :: Issues with Multisite Deployments :: Demo 3 Closed Caption 0h 43m
    45 CIPT2 :: Multi-Site Media Resources :: Music on Hold Closed Caption 0h 44m
    46 CIPT2 :: Globalization and Localization of Call Routing :: Part 1 Closed Caption 0h 34m
    47 CIPT2 :: Globalization and Localization of Call Routing :: Part 2 Closed Caption 0h 49m
    48 CIPT2 :: Globalization and Localization of Call Routing :: Part 3 :: Outbound Closed Caption 0h 40m
    49 CIPT2 :: Globalization and Localization of Call Routing :: Demo :: Inbound Closed Caption 1h 09m
    50 CIPT2 :: Globalization and Localization of Call Routing :: Demo :: Outbound Closed Caption 0h 54m
    51 CIPT2 :: Globalization and Localization of Call Routing :: Demo :: Free Features Closed Caption 1h 22m
    52 CIPT2 :: Extension Mobility and Device Mobility Closed Caption 1h 04m
    53 CIPT2 :: Call Control Discovery via SAF :: Overview Closed Caption 0h 29m
    54 CIPT2 :: Call Control Discovery via SAF :: CUCM Inter-Cluster Call Routing Closed Caption 1h 32m
    55 CIPT2 :: Call Control Discovery via SAF :: CUCM Call Routing with PSTN Failover Closed Caption 0h 29m
    56 CIPT2 :: Call Control Discovery via SAF :: CUCM Call Routing during SRST Fallback Closed Caption 0h 48m
    57 CIPT2 :: Call Control Discovery via SAF :: CUCM to CME Call Routing Closed Caption 0h 54m
    58 CIPT2 :: Call Control Discovery via SAF :: Inter-Cluster RSVP via SIP Preconditions Closed Caption 0h 21m
    59 CAPPS :: Unity Connection Integration Options Closed Caption 1h 01m
    60 CAPPS :: Unity Connection Users and Mailboxes Closed Caption 1h 08m
    61 CAPPS :: Unity Connection System Call Handlers and Audio Text Closed Caption 0h 58m
    62 CAPPS :: Unity Connection :: Misc Items Closed Caption 0h 25m
    63 CAPPS :: Unity Express Integration and User Mailboxes Closed Caption 0h 54m
    64 CAPPS :: Messaging - Voice Profile for Internet Mail (VPIM) Networking between Unity Connection and Unity Express Closed Caption 0h 32m
    65 CAPPS :: Unified Presence Server Closed Caption 1h 10m
    66 TVOICE :: Fundamentals of Troubleshooting UC Closed Caption 0h 36m
    67 TVOICE :: Troubleshooting of Enpoint Issues Closed Caption 0h 28m
    68 TVOICE :: IOS Gateway Debugging Closed Caption 0h 16m
    69 TVOICE :: UCM Traces and Alarms :: Demo Part 1 Closed Caption 0h 51m
    70 TVOICE :: UCM Traces and Alarms :: Demo Part 2 Closed Caption 0h 46m
    71 TVOICE :: UCM Traces and Alarms :: Demo Part 3 Closed Caption 0h 46m
    72 TVOICE :: UCM Traces and Alarms :: Demo Part 4 Closed Caption 1h 09m
    73 TVOICE :: UCM Traces and Alarms :: Demo Part 5 Closed Caption 0h 19m
    Total Duration   62h 49m
  • 0:00:13 For our next section on C Voice, gateways, trunks and signaling.
    0:00:22 So, taking a look at basic gateway functionality.
    0:00:25 The idea of a gateway in a voice network is to provide just that.
    0:00:29 A gateway between some sort of the separate networks.
    0:00:33 Be they traditional telephony networking protocols, and newer Voice over IP protocols,
    0:00:39 along with CUCM, the Unified Communication Manager.
    0:00:43 Or possibly to switch voice channels between an analog and digital voice circuits.
    0:00:50 Maybe to interconnect two separate Voice over IP networks.
    0:00:54 They also provide for call survivability and things such as fax and modem services.
    0:01:01 They also provide for something called DSPs, Digital Signal Processors,
    0:01:06 which we talked a little bit about in CCNA voice and we're gonna go into great detail here in NP voice.
    0:01:17 Taking a look at voice and video gateway hardware just to begin with.
    0:01:22 And this is specific to Cisco's implementation.
    0:01:28 The primary gateway hardware the we use is either the slightly older ISRs or Integrated Services Routers.
    0:01:38 The 2800 and 3800 series routers, or the newer ISR G2.
    0:01:44 The Generation 2.
    0:01:45 The 2900 and 3900 series Cisco routers.
    0:01:53 We also have special usage type gateways.
    0:01:57 One being the ATA or Analog Terminal Adapter, 186 is just the number that goes along with it.
    0:02:04 And this provides for two FXS Ports, something we're gonna talk a lot more about,
    0:02:09 basically being an analog phone port and a very small compact form factor.
    0:02:18 We also have the VG 248 or Voice Gateway 248.
    0:02:22 This provides for 48 FXS ports as well as an SMDI serial port.
    0:02:29 There's also the seemingly smaller but actually a little bit newer VG 224,
    0:02:37 which provides for only 24 FXS ports but has newer more capable DSPs on board.
    0:02:46 We also have the AS...
    0:02:49 5350 XM.
    0:02:51 This is for much larger deployments.
    0:02:55 As well as the AS 5400 XM for very large deployments.
    0:03:01 And depending on how large our deployments are, we can even go up to the 7206 VXR series.
    0:03:08 Okay, this can have multiple DS3s or voice channels terminating here in this router.
    0:03:17 So, looking at some common voice and video gateway modes, we really have three primary voice or video gateway modes.
    0:03:25 And that is voice switching, we're going POTS-to-POTS VoIP gateway,
    0:03:31 where we are going from either IP to POTS.
    0:03:34 POTS being the plain old telephony system.
    0:03:37 Or from POTS to IP and then from the IP-to-IP gateway perspective.
    0:03:44 So, this is something Cisco calls the Unified Border Element.
    0:03:49 So, looking at voice switching going between two between types of POTS circuits.
    0:03:56 We might have the need to go between a analog circuit and a digital circuit,
    0:04:01 such as maybe an FXO and a T1 CAS, or an FXO and a PRI.
    0:04:08 Here, we show an example in the graphic of going from the SS7 Signaling,
    0:04:14 which is the System Signaling 7 basically what the traditional PSTN
    0:04:20 or Public Switching Telephone Network has used in the core of the network for years and years.
    0:04:29 Really decades, long before many carriers began going to IP in the core of their networks.
    0:04:37 But many and I might even argue still most carriers do use a lot of SS7 signalling.
    0:04:45 But we even have this ability on a corporate or enterprise side to interface with the tellcode,
    0:04:50 depending on the contracts and the types of hardware that we have integrate or interface with SS7 signaling.
    0:04:58 So, we could be going between SS7, and let's say, PRI.
    0:05:03 Again, these are all analog signaling types that we'll be talking a lot more about.
    0:05:08 The analog signaling being FXO, FXS and E&M.
    0:05:13 And the digital signaling just as an introduction to the terminology being ISTN PRI.
    0:05:20 ISTN Q.Sig, SS7 and not mention here but still important is CAS.
    0:05:32 Looking at Voice over IP gateway.
    0:05:35 We might have the need to terminate a connection to a PBX or possibly to the Public Switched Telephone Network,
    0:05:42 and convert to or from IP signaling.
    0:05:47 So, going from either digital or analog signaling out to the PSTN or may be interfacing with a PRI to a another PBX.
    0:05:57 Okay, so, we might be doing a integration or migration with an existing traditional telephony PBX.
    0:06:07 And then lastly, IP-to-IP gateway or as Cisco calls it now CUBE.
    0:06:12 The Cisco Unified Border Element.
    0:06:15 The idea is to interconnect two logically separate Voice over IP networks.
    0:06:18 Possibly between a corporate network and an Internet telephony service provider or between multiple ITSPs.
    0:06:30 It's also important to bear in mind that as we're looking at voice,
    0:06:33 we will primarily be looking at it from a corporate perspective,
    0:06:37 but that's not in any way to say that Cisco hardware doesn't easily scale up to as it's used in service provider networks.
    0:06:46 So, when we are looking at things...
    0:06:49 Again, we'll be looking at them primarily form a corporate perspective and interprise perspective,
    0:06:53 but some of the things that we'll be talking about or at least mentioning such as a 7 signaling...
    0:06:59 Such as, ITSP to ITSP, this can certainly be used in large scale service provider networks.
    0:07:08 Now, the way that voice gateway...
    0:07:10 Cisco voice gateways interact with these different types of telephony, whether they are the older POTS,
    0:07:18 the Plain Old Telephony System, or the newer PANS, the Pretty Advance New Stuff.
    0:07:24 That's kind of a lame joke.
    0:07:25 You have POTS, you have to have PANS and a kitchen.
    0:07:27 Anyhow, the IP based signaling is with dial peers.
    0:07:33 And the most used dial peer types are again, POTS, Plain Old Telephone System.
    0:07:40 This maps a dial string to a specific voice port on a local gateway,
    0:07:46 and then the actually physical voice port connects the gateway
    0:07:49 to either to the PSTN or a PBX or possibly an individual analog telephone.
    0:07:57 We have VoIP dial peer types and this points to the IP address or DNS server or DNS name, really.
    0:08:05 Fully qualified domain name of the destination device that we're trying to terminate our connection on.
    0:08:14 And it maps and applies various Voice over IP protocols such as H.323 or SIP.
    0:08:23 And then we also have a little bit less used type, typically used in faxing but certainly still valid to discuss,
    0:08:31 which is the MMoIP, the Multi-media Mail over IP.
    0:08:36 And this dial peer points to the E-mail address of an SMTP server.
    0:08:41 It's used primarily as I mentioned for Storm Forward Faxing.
    0:08:44 What's known as On Ramp and Off Ramp Faxing.
    0:08:47 Something that we will be closing this voice gateway signaling and trunks lecture with is the faxing.
    0:08:59 So, I wanna take a brief look and do a comparison between IP based routing and call routing.
    0:09:06 Now again, presumably you already watched or have at least have the understanding of the CCNA voice level knowledge.
    0:09:14 But even though you have probably gone ahead and watched that and take in the associated exam,
    0:09:21 you probably still have more of a background in data.
    0:09:25 Now, it may not necessarily be the case, you might come from the voice side of the world.
    0:09:30 But assuming that you do have a good understanding of data,
    0:09:33 I wanna take kind of a look at the IP routing side,
    0:09:37 the data side of things and compare that to the call routing side of things.
    0:09:43 Or the telephony side.
    0:09:44 So, on the IP routing column, we've got this idea of static IP routing, or dynamic routing.
    0:09:52 In call routing, in voice networks, we also have static routing or dynamic routing.
    0:09:58 Now, up until version 8 of the UC...
    0:10:02 Of Cisco's Unified Communication platforms, we really only had static call routing.
    0:10:08 With version 8, we'll certainly see...
    0:10:11 Once we get to the third main module, CIPT2 that with things such as SAF and CCD, Call Control Discovery,
    0:10:19 we now have dynamic routing of calls as well.
    0:10:23 In an IP routing world or a data world, we have an IP routing table.
    0:10:29 In a voice world, we have a dial plan.
    0:10:34 In a data world, we have an IP route.
    0:10:37 In the voice world, we have a dial peer.
    0:10:40 In the data world, we do hop-by-hop routing so, each router makes an independent decision based on the SEF table
    0:10:47 or routing information base and in the voice network, we have basically what we called call legs.
    0:10:53 And then that is that gateways are not independently responsible,
    0:10:57 but they actually must negotiate with the preceding router or with the next router,
    0:11:01 depending on if it's an inbound or an outbound call leg.
    0:11:05 Something that we're going to be taking a lot more of a look at here in just a moment.
    0:11:11 In the data world, we had destination based routing.
    0:11:16 Based on IPs.
    0:11:17 The destination IP.
    0:11:19 In the voice world, we have called number.
    0:11:22 So, it's destination based routing but based on the destination pattern or the number that is being dialled by the caller.
    0:11:31 In the data world, we had the longest matched IP rule.
    0:11:36 So, if I had a route to,, that's certainly a valid route.
    0:11:47 However, if I have a route to, all my host bits or subnet bits are flipped to on.
    0:11:56 Okay, /32, that's a longer route.
    0:12:00 In the voice world, we have the same concept.
    0:12:04 And we're gonna go over and take a look at it much more in depth especially when we get into CIPT1.
    0:12:09 But we have this idea of the longest matched number rule.
    0:12:12 Now, in UCM, that is the Unified Communication Manager,
    0:12:18 it pretty much stays the longest matched rule.
    0:12:22 It's a pretty much a hard and fast rule.
    0:12:23 And again, we'll take a look at that in CIPT1.
    0:12:26 Here in C voice, we're gonna see that, that can be change.
    0:12:30 Now, that's only able to be changed on the voice gateways.
    0:12:33 So, it depends on the platform that we're taking a look at as...
    0:12:38 I should say, it depends on the component of the UC network whether or not something can be allowed or not.
    0:12:45 So, the idea of a longest matched is fairly hard and fast in the Unified Communication Manager,
    0:12:51 formerly called Call Manager by the way, if throughout the few weeks or many hours of videos,
    0:12:58 I happen to say, Call Manager.
    0:13:01 What I mean is, Unified Communications Manager.
    0:13:04 Okay.
    0:13:05 Unified Communication Manager or Cisco Unified Communication Manager is of course what Cisco calls it today,
    0:13:11 but for years and years they called it what it was, when they acquired it which was Call Manager.
    0:13:17 So, forgive me if I slip up and revert to old habits.
    0:13:22 In the data side, we have backup IP PADS, we also have equal cost PADS for our data to travel down.
    0:13:29 In the voice world, we have backup call routing PADS or possibly equal PADS.
    0:13:36 Now, we don't really divide our voice and send it equally along each side,
    0:13:40 but we can do something called load balancing of calls.
    0:13:43 So, one call goes here, the next call goes here.
    0:13:47 In fact, that's what we're gonna take a look at next.
    0:13:50 And in the data side we have what's known as a default route.
    0:13:54 And in the voice side, it's not normally the configuration but we certainly do have that option of a default call route.
    0:14:09 So, let's begin by taking a look at call routing PADS and we're gonna start with equal cost PADS or load balancing.
    0:14:17 So, may be I have over here on the right, I can see that I've got my two Unified Communication Managers,
    0:14:24 and obviously, in a much larger deployment that we'll talk about in CIPT1,
    0:14:29 we talk about deployment, redundancy and such.
    0:14:32 We would have more than two.
    0:14:34 But just for this example, may be I have two call processing engines that is two UCM servers running the CCM
    0:14:44 or Cisco Call Manager service and they've got the IPs of and
    0:14:55 Now, with the idea of equal load balancing, I could make a first call to 2001
    0:15:03 and my dial peer of the type Voice over IP or VoIP, might have a destination pattern that allows me to dial that.
    0:15:11 And again, we'll be taking a look at some of these options.
    0:15:14 So, if I don't go over every single new ones have the dial peer right now.
    0:15:20 Please allow that and forgive that because we will be going over them in much more detail,
    0:15:24 but I wanna take a look at them as we come to them.
    0:15:27 So, a destination pattern that allows that call
    0:15:30 and the session target points to the IP address of the first communication manager.
    0:15:38 And may be my second call to 2001 has a similar pattern or same pattern really and same preference.
    0:15:47 And because of the same pattern and the same preference, we're able to load balance these calls back and forth.
    0:15:54 So, the third call will go back to the first Communication Manager, the same place the first call went to.
    0:16:00 And the forth call will go to the second, the same place that the second call went to.
    0:16:07 Okay, we also have the idea of backup PADS.
    0:16:12 So, that is to say, maybe my primary call to 2001 goes across a Voice over IP dial peer across the WAN or Wide Area Network.
    0:16:23 Or LAN if that happens to be what we have.
    0:16:25 The idea of a backup though tends to be across the WAN because we tend to backup across the PSTN over the...
    0:16:34 Only if we're going across a large distance such as a WAN.
    0:16:41 So, the idea is if the WAN goes down, we have the ability to have a backup.
    0:16:46 So, notice my destination pattern...
    0:16:48 Oops!
    0:16:49 Sorry.
    0:16:49 My destination pattern is the same, and my preference, zero being the highest preference and also the default.
    0:16:59 one being a lower preference basically, if my Voice over IP dial peer, the session target is unreachable,
    0:17:07 basically because I do not have an IP path, and I don't have an IP path because my WAN circuits gone down,
    0:17:12 and my routing protocol has effectively taken that route out of my router,
    0:17:19 I cannot reach that session target, so I will as a secondary preference, or a lesser preference,
    0:17:26 I will backup over the PSTN.
    0:17:30 So, taking a look at dial peers, there's always two call legs to every gateway.
    0:17:37 So, every time a call crosses a gateway of any sort, whether it's a voice switching gateway,
    0:17:43 a gateway between the TDM which is Time Division Multiplexing.
    0:17:50 We'll go over that in much more great detail a little bit later.
    0:17:55 But the older TDM and the newer Voice over IP or even IP-to-IP gateway.
    0:18:02 The idea is that there's always an inbound call leg and an outbound call leg.
    0:18:08 Now, whether we're looking at an IOS voice gateway.
    0:18:11 So, that's an IOS router.
    0:18:14 UCM itself, the Unified Communication Manager.
    0:18:18 CME, Communication Manager Express, which is really not much more than software running in the IOS routers.
    0:18:27 Each and everyone of these are gateways.
    0:18:31 So, let's take a look at a WAN call and let's take a look at the outgoing gateways perspective of a call leg.
    0:18:40 So, first of all, let's just talk about the terminology OGW and TGW.
    0:18:46 So, OGW is, I said outgoing but really what I mean to say is originating.
    0:18:51 OGW is the originating gateway.
    0:18:55 TGW is the terminating gateway.
    0:18:57 So, the originating gateway is always the one that begins the call
    0:19:01 and the terminating gateway is the one that always receives and terminates that call.
    0:19:06 Now, in the voice world, it's important to note that the world terminate does not mean discontinue.
    0:19:13 Terminate means to really, just like you would terminate a wire on to a terminal.
    0:19:19 Okay.
    0:19:20 Or unto a 66 or 110 block.
    0:19:22 So, I'm punching down a connection of sorts even if it's a logical connection,
    0:19:29 and sometimes I might refer to it as nailing up a connection.
    0:19:33 But I'm making a connection.
    0:19:34 So, terminating a connection really in this sense means that we have a live connection.
    0:19:41 When I'm ready to tear down that call then I will do just that.
    0:19:45 Tear it down.
    0:19:46 But I won't refer to terminate a call as getting rid of a call or making it go away.
    0:19:52 Okay.
    0:19:53 Terminating really means nailing up or establishing a call.
    0:19:57 So, the originating gateway. we're taking a look from its perspective.
    0:20:02 So, just from the perspective of the originating gateway, if I have a call that comes in.
    0:20:07 Let's say, 2001 is , I've got my inbound call leg.
    0:20:13 So, maybe my inbound call leg looks like this.
    0:20:15 Dial peer voice 20001.
    0:20:18 Now, we'll take a look at this a little bit more later with the UCME, Unified Communication Manager Express,
    0:20:26 but we will note in that, that skinny based or SCCP based phones really result in POTS dial peers on CME.
    0:20:40 And so, where that POTS dial peer is...
    0:20:45 Or where the call is coming in is on that POTS dial peer.
    0:20:49 So, the inbound dial peer in this case is a POTS dial peer and Ephone DN.
    0:20:57 Then, the outbound call leg is in this case a VoIP dial peer.
    0:21:03 So, we've already taken a look at this dial peer basically destination pattern 2...
    0:21:08 So, 2 and then any three digits.
    0:21:11 It's got its Voice over IP session target.
    0:21:14 So, from the perspective of the router that the call came in on POTS dial peer 20001,
    0:21:21 and it left on dial peer Voice over IP type 100.
    0:21:26 Now, that very same call from the perspective of the terminating gateway looks a little bit different.
    0:21:34 But the point is that each gateway has their own independent view of an inbound and an outbound call leg.
    0:21:42 So, that terminating gateway's perspective when the call came across,
    0:21:47 the inbound call leg was from the egress of the originating gateway to...
    0:21:54 And this is where we are perspective from the terminating gateway is to my ingress here.
    0:21:59 So, the call came in on a Voice over IP dial peer.
    0:22:04 And...
    0:22:05 So, the call came in Voice over IP dial peer 10.
    0:22:08 Animation is slightly off.
    0:22:10 And it left on dial peer 20000.
    0:22:13 Actually, this looks like 200,000.
    0:22:15 So, I typed in one too many zeroes.
    0:22:17 20005 is what that would have been.
    0:22:21 And that's a POTS dial peer.
    0:22:22 So, basically, these are two CMEs.
    0:22:25 But again, the important point being there's always two call legs and those call legs are going to be different,
    0:22:32 depending on the perspective of what gateway it is we're looking at.
    0:22:38 Okay.
    0:22:39 So, let's take a look at a PSTN call.
    0:22:42 So, first, the outgoing gateway's perspective of a PSTN call.
    0:22:47 Let's say, a 2001 is , the inbound leg stays the same, it's coming in over 20001, a POTS dial peer.
    0:22:55 But it's leaving over a also a POTS dial peer.
    0:23:00 And this time, it's going over the PSTN.
    0:23:03 The Public Switched Telephone Network and in this case, it looks like from our...
    0:23:08 From what I put is a...
    0:23:11 Nomenclature for the POTS type dial peer or POTS type circuit, it's 000:23.
    0:23:20 This looks like a PRI.
    0:23:24 And we'll get into a little bit more of how this dial peer's working in a little bit.
    0:23:30 Again, the PSTN call from the terminating gateway perspective,
    0:23:34 a call comes across, the inbound call leg.
    0:23:38 I forgot to change this, it's not Voice over IP dial peer, it is a POTS dial peer.
    0:23:43 So, here I have my incoming called number and direct inward dial statement,
    0:23:47 and my outgoing dial peer's still the same and still numbered incorrectly.
    0:23:52 20005 really not 200005.
    0:23:58 200000 dial peer is a lot of dial peers to have in a router.
    0:24:01 50 dial peer is a lot of dial peers to have in a router.
    0:24:05 You'll soon see.
    0:24:07 So, taking a look at how do we matched inbound dial peers?
    0:24:12 And we looked a little bit of at this in the CCNA voice, but it's important to go over it again
    0:24:19 and really understand this.
    0:24:21 That if the dial peer type is Voice over IP, or it's a digital TDM type of POTS dial peer.
    0:24:30 Okay, if it's an analog FXO, FXS then this doesn't really apply.
    0:24:37 But of the dial peer is VoIP or a digital POTS,
    0:24:40 then the first thing that we look at is the incoming called number command on the dial peer.
    0:24:46 If we see incoming called number, and we have a match,
    0:24:50 that is the highest or best choice and the call will match that dial peer
    0:24:55 and choose that dial peer as the inbound dial peer.
    0:24:58 And I should actually go back one slide and just specify that there's no way to in IOS,
    0:25:06 to specify whether a dial peer is a inbound or outbound dial peer.
    0:25:12 That is to say, there's no way to hard code this information.
    0:25:15 We don't inform dial peers that they are to be used for inbound or outbound.
    0:25:20 What we do is we configure commands like this, one of this on here.
    0:25:26 And this...
    0:25:28 The IOS basically goes through and chooses which dial peer matches best.
    0:25:33 So, it's our job as administrators or configuration professionals to input the commands necessary
    0:25:41 to help the router make the best informed decision of which dial peer it should match,
    0:25:47 but it's just important to note that we don't say...
    0:25:49 Any sort of a command...
    0:25:51 We don't enter any sort of a command like inbound dial peer or outbound dial peer.
    0:25:55 We don't specify what they are.
    0:25:57 So, really, any dial peer could be an inbound or an outbound dial peer depending on the logic that we have...
    0:26:08 The configuration that we've input already into these dial peers as to how they should match.
    0:26:14 We can certainly debug and understand what they will matched based on certain debug.
    0:26:22 So, one being probably the best being debug VoIP dial peer.
    0:26:28 And we can see what the router is choosing.
    0:26:31 What its options are and what it finally chooses.
    0:26:36 And it should actually even be noted before we go on that a single dial peer,
    0:26:41 although it's not necessarily always the best design.
    0:26:44 Sometimes it can be a very good design, but a single dial peer might be chosen
    0:26:50 as both the inbound and the outbound dial peer.
    0:26:53 It's really no different than saying a single IP interface could be chosen as both the inbound and the outbound.
    0:27:02 We might have a next hop router and, let's say, I am that router in a packet comes to me on my Fast Ethernet 00 interface,
    0:27:10 and based on my routing information table or SEF table,
    0:27:13 I forward that packet back out the Fast Ethernet 00.
    0:27:18 So, it could come in and leave the same interface, same thing with dial peers.
    0:27:23 It could come in one dial peer and leave the same dial peer.
    0:27:28 So, if the dial peer matches incoming called number command, that's the primary choice.
    0:27:34 And this matches the called number.
    0:27:36 We sometimes preferred a called number as DNIS or Dialed Number Identification Service.
    0:27:41 Now, you'll see those terms interchangeable used number and DNIS,
    0:27:46 and you'll see the terms calling number and ANI.
    0:27:49 Sometimes, I will leave and refer to then interchangeably.
    0:27:54 You could almost always refer to something as called number.
    0:27:56 DNIS isn't always necessarily the best or the most accurate representation of something,
    0:28:02 it depends on the protocol it's using but most everyone in the voice world will understand what you mean,
    0:28:08 when you say DNIS or ANI.
    0:28:11 Some people call it ANI, some people call it ANI.
    0:28:14 So, the next command, the next preference after incoming called number.
    0:28:20 If incoming called number does not matched, is answer address.
    0:28:24 So, answer address, while it seems like this is the person answering.
    0:28:29 So, it seems like it might be the called number, it's actually matching calling number or ANI.
    0:28:37 Next, preference after answer address, if it did not matched.
    0:28:41 Or we didn't have it configured, is destination pattern.
    0:28:45 Destination pattern, you might be surprise to be reading that it matches calling number or ANI.
    0:28:52 And that's because you would be used to seeing destination pattern matched the called number,
    0:29:00 and that's true that destination pattern does matched called number if the dial peer type is an outgoing dial peer type.
    0:29:08 Another words, if IOS is evaluating, what desk or...
    0:29:12 I'm sorry.
    0:29:13 What dial peer is the best for an outbound dial peer.
    0:29:18 First of all that means that IOS is already chosen an inbound dial peer,
    0:29:23 and now it's needing to choose an outbound dial peer.
    0:29:26 And destination pattern is what is chosen to matched an outbound dial peer,
    0:29:32 and it does matched destination pattern against called number.
    0:29:36 However, if we're not yet ready to match an outbound dial peer.
    0:29:42 Okay, we're not ready to match an egress interface.
    0:29:44 First, we have to match an ingress interface.
    0:29:47 We have to take the call in over an inbound dial peer of some type.
    0:29:52 If destination pattern is the only possible choice.
    0:29:57 Another words, incoming called number did not matched or was not configured,
    0:30:00 answer address did not matched or was not configured.
    0:30:02 Destination pattern can be considered but it matches the opposite when it is used for inbound.
    0:30:11 That is to say, it matches calling number.
    0:30:14 So, the destination pattern command is used to matched calling number on the inbound,
    0:30:18 and called number on the outbound.
    0:30:23 Finally, if none of those three are either configured or matched, then there is a single port command.
    0:30:32 Now, this is really only used for POTS dial peers because Voice over IP dial peers do not have a port.
    0:30:39 POTS dial peers have a physical port.
    0:30:42 Voice over IP dial peers, really don't have a physical port.
    0:30:46 They have a logical connection but we don't consider that as a port.
    0:30:52 Okay?
    0:30:54 And then actually, finally, finally.
    0:30:57 Is something called the default dial peer.
    0:30:59 Now, this is a none configurable and actually none viewable dial peer.
    0:31:05 You won't see it with any show commands.
    0:31:08 Debug dial peer, debug VoIP dial peer is something that could indicate whether that the default dial peer is been matched.
    0:31:17 But there is something called the default dial peer and this allows calls to come in,
    0:31:24 and terminate on a default dial peer.
    0:31:27 Now, really, this default dial peer is bad.
    0:31:30 Okay?
    0:31:31 It matches just about anything.
    0:31:36 It matches any codec, it allows for no DTMF relay whatsoever.
    0:31:44 DSCP for quality of service that we'll discuss later is marked as Zero.
    0:31:49 VAD, something we'll talk about a little bit later, which stands for Voice Activity Detection,
    0:31:54 and it's historically referred to that VAD is bad, depends on what your talking about.
    0:32:01 If we're talking about newer video systems like tele-presence and better algorithms
    0:32:06 then VAD can certainly be used and very good.
    0:32:08 But for most of telephony with decent size pipes.
    0:32:12 I should say, most audio telephony, we don't really want VAD too much.
    0:32:17 No RSVP support for called admission control.
    0:32:21 We can't trigger any sort of tool command language TCL or voice XML applications.
    0:32:28 And it doesn't have direct inward dialing.
    0:32:31 Which we're gonna talk about next.
    0:32:33 So, the ideas that we should always explicitly configure in matching inbound dial peer for both POTS and for Voice over IP.
    0:32:42 We don't want to allow the default dial peer to matched.
    0:32:49 So, let's take a look at direct inward dialing or DID versus two stage dialing.
    0:32:56 So, the idea of two stage dialing, a call comes into a gateway, presumably over a POTS TDM link from the PSTN.
    0:33:07 And then the caller here is a second dial tone.
    0:33:10 And when they hear a second dial tone, they have to dial again to match an internal pattern.
    0:33:17 So, they already went off hook and we'll talk a little bit more about that,
    0:33:21 but let me just go ahead and clarify as I say, off hook or on hook,
    0:33:25 for those of you who might not have much of a background in telephony,
    0:33:29 I wanna make sure that this is clear.
    0:33:31 Think of the 1910 or 1905 phone system that was in a house or some sort of public post office.
    0:33:44 And you actually had a mouth piece that you spoke into at about...
    0:33:50 About eye-level, about mouth level.
    0:33:52 And then you have a separate ear piece that was on an actual hook on the side of that...
    0:33:59 Big wooden box.
    0:34:01 And when you would lift up that ear piece, you would take the ear piece off the hook.
    0:34:07 Okay?
    0:34:08 And so, that's what we mean when we say going off hook.
    0:34:12 It means picking up the phone and all the sudden you hear on a properly configured system you hear dial tone.
    0:34:18 Okay?
    0:34:19 When we say going on hook, that means to hung up a call.
    0:34:23 So, off hook means pick up a call and start a call.
    0:34:25 On hook means to hung up a call.
    0:34:28 Although we certainly don't use a hook and an ear piece anymore in that old fashion,
    0:34:34 we still refer to things in the telephony world as off hook and on hook.
    0:34:38 So, a user goes they pick up the phone, they hear dial tone,
    0:34:43 they dial the number, the call reaches your voice gateway through the PSTN and all the sudden they hear a second dial tone.
    0:34:52 Now, aside from being confused if they were informed then they could go ahead and dial digits again,
    0:35:02 and actually gets somewhere in your phone system.
    0:35:04 And this does allow for possible toll fraud.
    0:35:07 Because they could potentially, depending on how your other system configured,
    0:35:10 dial anywhere versus you basically telling them where that call should go.
    0:35:16 Now, the idea of a direct inward dial, the call comes in to the gateway over the PSTN,
    0:35:23 and the DNIS or called number is passed directly on to the digit analysis engine.
    0:35:30 So, DID is something that's automatic for Voice over IP dial peers.
    0:35:34 We don't need to configure it, we can't tell it not to configure.
    0:35:38 However, for POTS, this is actually only supported on digital links such as T1 or E1 CAS,
    0:35:46 or T1 or E1 ISTN and then also one other analog type known as FXS DID.
    0:35:54 It's a specific type of FXS known as DID.
    0:35:58 So, it's not supported on traditional analog E&M, FXO, or FXS.
    0:36:04 Again, analog signaling that we're going to be talking much more in depth about.
    0:36:14 So, E&M is typically used for something known as tie trunks.
    0:36:18 The ability for us to take a trunk or a circuit and tie up two different PBXs together.
    0:36:27 So, that is directly connect two PBXs through a form of a permanent trunk.
    0:36:32 This is known as a tie trunk.
    0:36:34 So, it's not usually a concern.
    0:36:38 Or it's used for paging or some other analog voice functionality.
    0:36:43 FXS, Foreign Exchange Station is typically used to attached to an analog station.
    0:36:50 So, again, it's not usually a concern when someone picks up or goes off hook on that analog station,
    0:36:56 they're feeding the system digits of where they want to go.
    0:37:01 FXO however, is a call coming in from the PSTN and that call needs to be routed somewhere,
    0:37:09 and since we can't allow the digits that the person originally dialed to the passed on inbound to the system,
    0:37:17 to our voice gateway and used by the digit analysis engine for further routing.
    0:37:22 What we do is when that call comes in through an FXO port from the PSTN,
    0:37:28 we use a command called connection PLAR.
    0:37:32 Now, the acronym PLAR, P-L-A-R, stands for Private Line Automatic Ring down.
    0:37:42 Now, the concept behind PLAR, or Private Line Automatic Ring down is the idea of the BAT phone.
    0:37:48 Okay?
    0:37:50 If you haven't watched the old, 1950's Batman, then well, shame on you, really.
    0:37:57 No.
    0:37:58 I'm just kidding.
    0:37:59 But, the idea was that, at any time, Commissioner Gordon could just pick up that red phone
    0:38:05 and it would automatically call Batman.
    0:38:07 It didn't dial anything, there weren't even any...
    0:38:10 There wasn't even a rotary or any DTMF digits or any buttons, nothing on the phone.
    0:38:15 All you did was go off hook on that and it automatically called someone.
    0:38:19 So, that's what Private Line Automatic Ring down is.
    0:38:23 And we certainly have the ability to do that, not only in IOS voice gateways,
    0:38:29 which is what we're primarily talking about here for C voice.
    0:38:33 But then, also we have the ability to do that in UCM and we will take a look at that in our CIPT1 segment.
    0:38:41 But here, with a FXO, we basically say that if a call comes in on that type of a port, FXO,
    0:38:47 we're going to send it to one location.
    0:38:50 Probably a hunt pilot that's going to ring some sort of a hunt group.
    0:38:54 But that's the command we used connection PLAR to get that call to route somewhere.
    0:39:03 Now, we've already mentioned this but matching outbound dial peers is used or is done with the destination pattern command,
    0:39:13 and we matched the called number.
    0:39:16 Sometimes I put the inflection insert in my training videos I say call led.
    0:39:21 and I've had students in class says, "Is that really how you pronounce that call led or called?"
    0:39:27 And it's not so much that, that's the way I normally say it.
    0:39:30 I normally say things like calling and called.
    0:39:33 But when you say these very quickly, calling and called sometimes they can be mistaken what you meant.
    0:39:39 So, sometimes I'll put inflection on that.
    0:39:41 Don't think I'm weird in the way I say it.
    0:39:44 But again, destination pattern matches called for outbound and calling for inbound dial peers.
    0:39:54 So, let's take a look at actual IOS dial peer pattern matching.
    0:40:00 So, first of all, we have the ability to match all standard DTMF characters.
    0:40:06 Now, you're familiar with a regular DTMF keypad on a phone, which allows for 123456789*0# (hash) or *0# (pound)
    0:40:25 however you wanna refer to it.
    0:40:26 Asterisks 0 octothorpe (*0#) is the actual terminology.
    0:40:31 Octothorpe is what the hash or pound is called.
    0:40:35 But there's also A, B, C and D.
    0:40:39 Those are valid DTMF characters and in a little while, we're actually gonna take a look at,
    0:40:44 I need to know the frequencies, the high and low frequencies that are used to make up the high and the low matricee
    0:40:53 to make up the dual tone in DTMF or Dual Tone Multi Frequency.
    0:41:00 But for right now, it is important to know that A, B, C and D are also frequencies that,
    0:41:06 while they don't exist on most traditional phone keypads are still valid DTMF characters.
    0:41:14 They're still valid dual tone multi frequency characters.
    0:41:17 And so, they can be used in voice systems to matched.
    0:41:22 Typically, you'll see this characters on an actual keypad of a tone generator or,
    0:41:30 specifically a DTMF tone generator.
    0:41:33 Or if you are trying to dial from system to system.
    0:41:38 Maybe I'm trying to take a call center or IVR application and have it dial another system and trigger a DTMF tone,
    0:41:48 that most regular user shouldn't be able to or aren't able to trigger that frequency.
    0:41:58 Okay, there's also the dot, the period.
    0:42:01 This is a wild card that matches any single digit.
    0:42:06 We also have the idea of a plus.
    0:42:09 Now, this can be used first, if it's the first character to indicate that we're using something called plus E.164 dialing.
    0:42:21 Now, if you are...
    0:42:24 If you ever traveled to Europe or you live in really in,
    0:42:27 Really not just Europe but most of the rest of the world aside from the US.
    0:42:31 The US doesn't used plus dialing too often even in GSM networks.
    0:42:38 We're not used to dialing plus 2 often.
    0:42:40 But, we certainly have the ability with most GSM cellular carriers to be able to dial on our mobile phones,
    0:42:53 a plus and then a full E.164 number.
    0:42:57 A full E.164 number begins with country code and then it goes on to contain a city code.
    0:43:03 Some people call it an area code and then the rest of the subscriber digits.
    0:43:09 Different countries and states have different terminology for what they call the rest of the digits
    0:43:16 whether it's an office code and a subscriber code or what have you.
    0:43:21 But the idea of a plus before everything indicates that,
    0:43:26 what is about to come next is a full proper E.164 number and the digits directly following the plus are in fact,
    0:43:34 the country code.
    0:43:38 Okay.
    0:43:38 So, we can use that in IOS dial peer matching.
    0:43:43 Now, this does depend on the version of IOS that you have.
    0:43:47 I'm trying to think when the plus was first supported.
    0:43:49 I believe it was 12.4(15) but it might be 12.4(20)T.
    0:43:56 But in any rate the plus can be used.
    0:43:59 Now, a plus can also and typically does unless modified or escaped.
    0:44:05 It typically denotes a regular expression or regexp.
    0:44:10 And plus means 1 or more of the previous character.
    0:44:17 If it's not first in the string.
    0:44:18 If it's first in the string, well, then it would be an insane regular expression.
    0:44:25 Because, you cannot have one or more of a previous character if it is the first character.
    0:44:31 You have to have a previous character in order to have one or more of it.
    0:44:34 Right?
    0:44:35 That makes sense.
    0:44:36 So, in IOS dial peers, if I'm keying in the destination pattern, let's say.
    0:44:44 And I put plus first, it's intelligent enough to know that it cannot be a regular expression,
    0:44:50 because there is no previous character.
    0:44:52 If it is after any character, then it indicates one or more of the previous character.
    0:45:00 So, if I have, let's say, 9 plus then that would indicate that I could have...
    0:45:06 I could not have...
    0:45:07 Simply have a 9 because a plus indicates one or more.
    0:45:11 Not zero or more.
    0:45:13 So, a plus or I should...
    0:45:15 Sorry.
    0:45:16 A 9 plus would indicate 99, or it would indicate 999 or 9999 and so on and so forth for ethernity
    0:45:28 If I had dot plus, then it would indicate any single digit,
    0:45:34 and by the way that dot does not match asterisks or hash.
    0:45:39 So, it would be a zero through 9 and then plus.
    0:45:42 Meaning whatever I could have any single digit and then more digits.
    0:45:47 So, basically, any infinite string length of digits but it has to contain digits.
    0:45:55 I can use a question mark also being a regular expression or regexp.
    0:46:00 Now, this means zero or one.
    0:46:03 Not zero or more but zero or one.
    0:46:06 So, we'll see places where I can used the question mark to be creative,
    0:46:12 I could use it for things like, including the city code or not including a city code,
    0:46:19 and the dial peer matches either one.
    0:46:23 Okay, we'll take a look at this more but, just know that it's a regexp or regular expression that means zero or one,
    0:46:30 of the previous character.
    0:46:33 Now, the percentage is a regular expression that means zero or more of the previous character.
    0:46:40 So, could be zero, could be one, could be two.
    0:46:44 There's also a caret, this is a regular expression that means...
    0:46:48 Now, by the way, if you starting to get bug down and thinking,
    0:46:52 "wait a minute, we're already talking about regular expressions,
    0:46:55 do we really need to know these things?"
    0:46:58 Well, yes unfortunately, you do.
    0:47:00 And I realize that the...
    0:47:04 The CCNP voice course can sometimes be a bit like drinking from a fire hose,
    0:47:11 and that you're trying to ingest a lot of information in a short periods of time.
    0:47:17 So, this is the reason that we have these as recordings and you can go back and watch them again and again,
    0:47:22 as well as watch them side by side along with an actual terminal into a router
    0:47:28 or UCM if that's what we happen to be looking at, at the moment.
    0:47:31 And practice and pause and watch this and practice along with.
    0:47:37 But, if you actually...
    0:47:39 If you're coming from may be a long time in the data world, may be you actually already have a CCNP,
    0:47:44 or possibly CCIE and route switch then...
    0:47:48 Especially if you have a CCIE then you know that regular expressions are noting to be feared
    0:47:53 and something that you use a lot in routing and switching as well.
    0:47:57 The least in BGP.
    0:47:59 So, anyway, the caret or circumflex as its actually called,
    0:48:04 is a regular expression that basically indicates the beginning of the line.
    0:48:09 Or beginning of a string.
    0:48:11 So, if I had a caret, or circumflex, before the rest of any of my digits,
    0:48:17 I'm indicating that whatever my first digit is, is actually my first digit.
    0:48:22 And it doesn't happened to come in the middle of a string.
    0:48:27 These are going to be more important...
    0:48:31 The caret is gonna be more important not necessarily as much when we do destination pattern matching,
    0:48:37 although it certainly could be.
    0:48:38 But more when we get into voice translation rules in IOS.
    0:48:43 So, we will be using these.
    0:48:46 And then just like we have a regular expression that indicates the beginning of a string,
    0:48:51 we have a dollar sign that indicates the end of the string or end of the line.
    0:48:55 Okay.
    0:48:57 So, the dollar sign indicates the end of the string.
    0:49:00 Now, one more.
    0:49:01 Those are all regular expressions.
    0:49:03 The plus, question, circumflex or caret and dollar sign, but they are...
    0:49:11 So, they're not specific to IOS in any way.
    0:49:15 Something that is specific to IOS, is the T.
    0:49:19 For inter-digit time-outs.
    0:49:21 It's a capital T, and this is used to indicate a wait that needs to occur for the inter-digit time-out.
    0:49:29 Now, what is the actual value of the inter-digit time-out?
    0:49:32 That just depends on what you have configured in IOS.
    0:49:39 Or what the default is.
    0:49:41 If you haven't configure anything more specific.
    0:49:44 And then we also have a very commonly used in much of programming across the Web is the back slash,
    0:49:51 which is to escape a character.
    0:49:54 So, if...
    0:49:56 Let's say, I'm using a plus.
    0:49:58 Now, we're...
    0:49:58 Right now, we're talking about dial peer matching but let's say, I want to use a plus in a...
    0:50:05 Something called a voice translation rule, something we'll take a look at much more in depth in a little while.
    0:50:13 If I wanted to use a plus as an actual plus, in a dial peer,
    0:50:18 then I can simply use it as the first character.
    0:50:21 If I wanted to use it anywhere else in the IOS, like let's say, a voice translation rule,
    0:50:27 I would need to escape it.
    0:50:29 So, I would put into escape and then a plus and that's going to indicate that the next character,
    0:50:35 the plus is actually used as an actual string character.
    0:50:39 So, it's actually suppose to match a plus and not perform the function of a regular expression.
    0:50:48 Also, I have the ability to nest things inside of a left and right square bracket.
    0:50:55 Now, the left and right square bracket.
    0:50:57 What this means is that, no matter how many digits I have in here.
    0:51:01 Whether I have a range such as zero through 9, or whether I have a series of,
    0:51:06 let's say, 3 or 4 or 5 digits.
    0:51:08 May be I have 239 or 75...
    0:51:13 5789.
    0:51:17 Whatever I have in those left-right square brackets that indicates a single digit.
    0:51:24 And what's in there are the possible digits that are able to match and become that single digit matched.
    0:51:32 But inside the left and right square bracket are a single digit,
    0:51:38 or single character that we're trying to match.
    0:51:41 Could be a asterisks or hash or A through D as well.
    0:51:46 And then I also finally have a left and right or open close parenthesis.
    0:51:52 Now, this is not a single digit, this is a collected pattern of digits.
    0:51:57 So, let's say, I wanted to, maybe I would use this with a regexp.
    0:52:01 May be I wanted to indicate a city code or an area code in...
    0:52:07 Let's say, a 10 digit number.
    0:52:09 I might use 206501....
    0:52:18 So, that's indicating the area code or city code is 206.
    0:52:23 The remaining digits or prefixes 501 and any four digits ....
    0:52:32 Now, maybe I wanted that pattern to matched both 10 digit numbers to begin with 206501,
    0:52:41 and actually, let me just draw this up here.
    0:52:48 So, may be I wanted it to match (206)501.. and
    0:53:00 I apologize but the PowerPoint does not allow me to draw very neatly at all.
    0:53:05 ....
    0:53:07 I could do something like (206) and then a regular expression like question.
    0:53:15 And so, this question is not a single digit place holder.
    0:53:20 What it's saying is that this collected group of digits 206,
    0:53:25 the whole collected range is either question.
    0:53:30 It's either zero or more...
    0:53:33 I'm sorry.
    0:53:33 Zero or one appearances.
    0:53:37 So, that means that if the 206 does not exist, zero, then the dial peer would still matched 501 and then ....
    0:53:52 Or it could matched one instance of that previous collected range of digits which because it was in the left-right,
    0:54:01 or open-close parenthesis, the collected range of digits 206,
    0:54:05 it this question indicated one instance of that, then it would matched not only 206501, let's say, 1111.
    0:54:17 But it would also match 5011111.
    0:54:23 So, we do have the ability to use collections or sets as we might also call them.
    0:54:30 Can use this with dial peers, we can use them with things called voice translation rules.
    0:54:36 In fact, I think I have some patterns examples coming up right now.
    0:54:42 So, let's take a look at...
    0:54:43 And again, this is not just for destination pattern where outgoing calls.
    0:54:48 We used the same types of patterns for inbound matching examples.
    0:54:53 So, first of all, I've got incoming called number dot.
    0:54:56 Now, this matches every incoming call.
    0:55:00 And you might have the question, why would it match every call.
    0:55:05 It should only match a call that has a single digit.
    0:55:08 Well, if we go back to the last slide, we might remember that unless we have specified the caret or circumflex,
    0:55:17 meaning the beginning or a string, and digits are strings.
    0:55:23 Okay?
    0:55:24 If we...
    0:55:25 Let me just clarify this real quick, take a step back and say...
    0:55:28 If we say...
    0:55:30 Let's say, we're coding a phone number.
    0:55:33 Let's just say, it's a 10 digit phone number, certainly it's not that length in all parts of the world,
    0:55:39 various countries and states have various length of full E.164 numbers.
    0:55:47 But let's just say for the sake of discussion that it's a 10 digit number.
    0:55:55 If I say...
    0:56:00 Let's say, I say the number is 2065011111.
    0:56:06 I don't...
    0:56:07 Let me just wide it out here.
    0:56:11 Oops!
    0:56:19 Okay, 206501, let's say, 1001.
    0:56:28 What I don't do is draw a comma after every three digits and say that this number is 2,000,065,000...
    0:56:42 I'm sorry.
    0:56:43 2,065,011,001
    0:56:47 That's not how I ever refer to a number.
    0:56:50 We never with phone numbers, we never actually draw those commas,
    0:56:55 we never refer to them as an integer.
    0:56:58 So, they are strings.
    0:57:00 and we do, what's actually in associative memory terms called blocking.
    0:57:06 And that is to say that humans typically cannot most average humans, you maybe extra average or extraordinary.
    0:57:14 But most average humans can't remember a number that is 10 digits long.
    0:57:20 They can't remember too many of them at least.
    0:57:23 But we have...
    0:57:24 We certainly can remember our first phone number from where we grow up in a house.
    0:57:30 We can remember many different phone numbers that we've had, and it's because of something called blocking.
    0:57:36 And, without getting too much into that, it basically has to do with the fact
    0:57:40 that this in our world is considered at least the telephony world is considered a string.
    0:57:47 Okay?
    0:57:48 So, if we were doing this in some sort of an application,
    0:57:50 we would put double quotes around it, because this is actually a string.
    0:57:55 So, when I refer to regular expressions that matched parts of a string, it's because our phone numbers are strings.
    0:58:03 So, we remember that because, we have this ability to have a caret or circumflex that matches the begining of the string,
    0:58:13 and a dollar sign that matches the end of the string, unless we have actually specified,
    0:58:19 the caret or the dollar sign, we have not specify the beginning or end of the string.
    0:58:26 So, incoming called number dot only specifies the first digit
    0:58:32 and it means that it could be any digit in a string that could be any length.
    0:58:39 So, this is the reason it matches every incoming call.
    0:58:42 Now, if we were more specific and we said incoming call-number.$
    0:58:48 then this will only matched one digit.
    0:58:51 Well, technically, it would matched any number of digits coming before it but the way that the...
    0:58:57 IOS processes it, is the first digit would come in, matched and the dollar sign would say,
    0:59:01 that's the end and so the only time that would matched is if the actual called number or in this case...
    0:59:08 Yeah.
    0:59:09 Called number was exactly one digit which is rarely ever going to be the case.
    0:59:15 So, because we have the omission of the dollar sign,
    0:59:19 this is where incoming called number dot matches every incoming call.
    0:59:26 Now, if we have, let's say, destination pattern dot T.
    0:59:30 So, this is any digit and then T, which is the inter-digit time-out.
    0:59:34 This is going to matched every outgoing call to any DNIS, any called number or incoming from any ANI.
    0:59:43 Any calling number.
    0:59:45 However, specifically for outgoing or mainly for outgoing calls.
    0:59:50 And we'll talk about when it might occur for incoming later.
    0:59:53 But, specifically for outgoing calls, we would also have an inter-digit timer wait at the end.
    1:00:01 Okay so, we might be able to dial...
    1:00:06 92065015111, but once we dial our last digit, we would have to wait whatever this inter-digit timer was.
    1:00:18 So, then we have something like destination pattern +12065015111.
    1:00:26 So, here we've matched a very specific E.164 number with the plus.
    1:00:33 Here is the example that I actually just gave, which was the (206)
    1:00:43 So, I've got this set or collection of numbers,
    1:00:46 followed by a regular expression which indicates zero or one of the previous something.
    1:00:53 Previous character, but if it's a collection, that it indicates Zero,
    1:00:57 one of the previous collection.
    1:00:59 And then 5015111.
    1:01:02 So, this matches outbound DNIS or inbound calling ANI, to or from 2065015111 or just 5015111.
    1:01:14 Because the question could be zero of that previous set.
    1:01:18 Then I've got something like destination pattern caret 2065011...$
    1:01:28 So, again, it matches outbound DNIS or inbound ANI.
    1:01:32 Why, because destination pattern can be used to match incoming calling number or outbound called number,
    1:01:39 again to or from 2065011 and then any three digits.
    1:01:45 Which basically matches the entire 1000 range of DID.
    1:01:50 However, the pattern must begin with 2065011 and then only have three more digits.
    1:01:57 That's the circumflex, the caret and the dollar sign.
    1:02:03 And then here I've got my last example where I have 2065015 and then [12]..
    1:02:12 So, it can match again, either outbound DNS or inbound calling ANI from 2065015 and then that third...
    1:02:23 And this is something that we should just mentioned here real quick,
    1:02:28 which is the idea of significant digits.
    1:02:31 Significant digits begin from the right, most digit and proceed left.
    1:02:37 So, this is the most significant digit, the second most significant digit.
    1:02:42 So, what we're saying here is that the third most significant digit.
    1:02:47 Because this is not a parenthesis.
    1:02:49 Open-close parenthesis but instead a left-right bracket.
    1:02:51 It doesn't mean that it's a group of digits but rather a...
    1:02:57 This is a single digit place holder.
    1:03:00 And it can either be a one or a two.
    1:03:03 And then any two digits.
CCNP Voice - Version 8.0
Title: CCNP Voice - Version 8.0
Duration: 62h 49m
The CCNP Voice class is an ultimate all-in-one solution for engineers pursuing the Cisco Certified Network Professional Voice (CCNP Voice) certification. This Video-on-Demand course includes over 60 hours of instructor-led content that will fully prepare you for the latest Cisco CCNP Voice exams (642-427 TVOICE v8, 642-437 CVOICE v8, 642-447 CIPT1 v8, 642-457 CIPT2 v8, and 642-467 CAPPS v8) certification exam.
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