CCIE R&S Advanced Technologies Class v4.5

Transcript

1	Introduction	0h 43m
2	Using the Cisco Documentation	0h 52m
3	Ethernet Overview, Layer 2 Switchports, Trunking, ISL, 802.1q, DTP	0h 47m
4	VTP, VTP Authentication, VTP Pruning	1h 02m
5	VTP Prune Eligible List, VTP Transparent, VTP Troubleshooting, Trunk Allowed List, Extended VLANs	0h 48m
6	VLAN and VTP Review	0h 19m
7	SVIs, Native Routed Interfaces, Router-on-a-Stick	0h 46m
8	Layer 2 EtherChannel, EtherChannel Load Balancing, Layer 3 EtherChannel	0h 57m
9	802.1q Tunneling, Layer 2 Protocol Tunneling, EtherChannel over 802.1q Tunneling	1h 03m
10	STP Root Bridge Election, STP Root Port Election, STP Designated Port Election, STP Priority, STP Cost, STP Port-Priority	1h 46m
11	STP Review	0h 12m
12	STP Timers, STP PortFast	0h 34m
13	STP UplinkFast	0h 11m
14	STP BackboneFast	0h 12m
15	STP BPDU Filter	0h 13m
16	STP BPDU Guard	0h 11m
17	STP Root Guard	0h 11m
18	STP Loop Guard, Unidirectional Link Detection (UDLD)	0h 11m
19	Multiple Spanning-Tree Protocol (MST)	0h 40m
20	Rapid Spanning-Tree Protocol (RSTP), Rapid-PVST	0h 18m
21	MST with Multiple Regions	0h 33m
22	Flex Links	0h 16m
23	Frame Relay	0h 39m
24	Frame Relay Configuration Part 1	0h 34m
25	Frame Relay Configuration Part 2	0h 41m
26	Frame Relay Switching	0h 27m
27	Back-to-Back Frame Relay	0h 08m
28	Frame-Relay End-to-End Keepalives	0h 18m
29	PPP, PPP PAP Authentication, PPP CHAP Authentication	0h 59m
30	PPPoFR, PPPoE	0h 40m
31	Transparent Bridging, IRB	0h 32m
32	Fallback Bridging	0h 14m
33	IP Routing Overview, Switching Paths, Static Routing	0h 42m
34	Static Routing Examples	0h 25m
35	IP Default-Gateway, IP Default-Network	0h 14m
36	On-Demand Routing (ODR)	0h 07m
37	Floating Static Routes	0h 10m
38	Backup Interface	0h 29m
39	Enhanced Object Tracking, IP SLA, Reliable Static Routing	0h 21m
40	Policy Routing	0h 43m
41	GRE Tunneling, GRE Recursive Routing Errors	0h 27m
42	Reliable Backup Interface with GRE	0h 25m
43	RIP Overview, RIP Versions, RIP Auto-Summary	0h 48m
44	RIP Split-Horizon, RIP Timers	0h 22m
45	RIP Broadcast Updates, IP Directed Broadcast, IP Broadcast-Address, Smurf Attacks, Fraggle Attacks	0h 16m
46	RIP Unicast Updates	0h 03m
47	RIP Offset-List	0h 18m
48	RIP Authentication	0h 11m
49	RIP Summarization	0h 10m
50	Prefix-Lists, RIP Distribute-List Filtering, RIP Administrative Distance Filtering	0h 48m
51	RIP Default Routing, RIP Conditional Default Routing	0h 18m
52	RIP Triggered, RIP Validate Update Source,	0h 12m
53	EIGRP Overview	0h 29m
54	EIGRP Auto-Summary	0h 07m
55	EIGRP Split-Horizon	0h 11m
56	EIGRP Update Types, EIGRP Neighbor, EIGRP Passive-Interface	0h 24m
57	EIGRP Hello-Interval, EIGRP Hold-Time	0h 05m
58	EIGRP Authentication	0h 11m
59	EIGRP Time Based Authentication	0h 25m
60	EIGRP Path Selection, EIGRP Metric Weights, EIGRP Traffic Engineering	0h 47m
61	EIGRP Unequal Cost Load Balancing, EIGRP Variance	0h 19m
62	EIGRP QUERY, EIGRP Summarization, EIGRP Leak-Map	0h 28m
63	EIGRP Stub Router Advertisement	0h 22m
64	EIGRP Default Routing	0h 13m
65	EIGRP Route Filtering	0h 11m
66	EIGRP Router-ID	0h 07m
67	Miscellaneous EIGRP Features	0h 02m
68	OSPF Overview	0h 27m
69	Establishing OSPF Adjacencies, Understanding the OSPF Database	0h 43m
70	OSPF Network Type Broadcast, OSPF DR/BDR Election, OSPF over NBMA, OSPF Network Type Non-Broadcast and Point-to-Multipoint	0h 56m
71	OSPF Network Type Point-to-Point, OSPF Network Type Mismatch	0h 13m
72	OSPF Network Type Point-to-Multipoint Non-Broadcast, OSPF Per Neighbor Cost	0h 17m
73	OSPF Network Type Loopback	0h 02m
74	OSPF Path Selection	0h 27m
75	OSPF Convergence Timers	0h 09m
76	OSPF Authentication	0h 12m
77	OSPF Summarization	0h 32m
78	OSPF Stub Areas, OSPF Totally Stubby Areas, OSPF NSSAs, OSPF Totally NSSAs	0h 40m
79	Controlling OSPF NSSA Redistribution	0h 02m
80	OSPF Type 7 to 5 Translator Election, OSPF LSA Type 3 Filter, OSPF Forwarding Address Suppression	0h 24m
81	Route Redistribution Overview	0h 36m
82	Route Redistribution Configuration & Verification, Connected Redistribution	0h 22m
83	OSPF External Path Selection, TCL PING Scripting	0h 33m
84	Routing Loops Overview, EIGRP Route Loop Prevention	0h 55m
85	Metric Based Routing Loops, Route Tagging	0h 46m
86	Administrative Distance Based Routing Loops, Debug IP Routing, IP Route Profile	0h 58m
87	BGP Overview, BGP Peering Types	0h 51m
88	Establishing BGP Peerings, EBGP Multihop, BGP Neighbor Disable Connected Check, BGP TTL Security	0h 49m
89	BGP 4-Byte ASNs	0h 20m
90	BGP Local AS, BGP Peer Groups	0h 30m
91	BGP Next-Hop Self, BGP Next-Hop Processing	0h 30m
92	BGP Route Reflectors	0h 37m
93	Large Scale BGP Route Reflectors with Clusters	0h 34m
94	BGP Confederation	0h 37m
95	BGP NLRI Advertisements, BGP Network Statement, BGP Redistribution	0h 43m
96	BGP Aggregation, BGP Aggregation & Summary-Only, BGP Aggregation & Unsuppress-Map	0h 46m
97	BGP Origin, BGP Aggregation & AS-Set, BGP Aggregation & Advertise-Map	0h 22m
98	BGP Conditional Route Injection	0h 21m
99	BGP Bestpath Selection, BGP Multipath, BGP Weight	0h 53m
100	BGP Local Preference, BGP Local Preference and Communities, BGP AS-Path Prepending,	0h 30m
101	BGP MED, BGP MED Missing As Worst, BGP Deterministic MED	0h 17m
102	BGP Communites, BGP Regular Expressions	0h 43m
103	BGP Filtering, BGP Convergence Timers, BGP Default Routing, Miscellaneous BGP Features	0h 24m
104	MPLS Overview, MPLS Label Distribution Protocol (LDP)	1h 05m
105	MPLS Tunnels, MPLS Penultimate Hop Popping (PHP)	0h 40m
106	MPLS Layer 3 VPNs Overview, VRF Lite	0h 36m
107	MPLS Layer 3 VPNs and VPNv4 BGP	1h 08m
108	MPLS Layer 3 VPN Verification & Troubleshooting	0h 49m
109	MPLS Layer 3 VPN OSPF PE-CE Routing Overview	0h 06m
110	MPLS Layer 3 VPN OSPF PE-CE Routing Path Selection & Sham-Links	2h 01m
111	MPLS Layer 3 VPN OSPF PE-CE Routing Loop Prevention & Down-Bit, OSPF Capability VRF-Lite	0h 40m
112	IPv6 Overview, IPv6 ICMPv6 ND, IPv6 over NBMA	0h 44m
113	IPv6 Routing Overview, IPv6 Static Routing	0h 28m
114	IPv6 RIPng	0h 20m
115	IPv6 EIGRPv6	0h 09m
116	IPv6 OSPFv3	0h 31m
117	MP-BGP for IPv6	0h 26m
118	IPv6 Tunneling	1h 13m
119	Multicast Overview, IGMP	0h 34m
120	PIM Overview	0h 18m
121	PIM Dense Mode	1h 03m
122	PIM Sparse Mode	0h 30m
123	PIM Sparse Mode Configuration	0h 36m
124	PIM Sparse Mode RPF & RP Troubleshooting	0h 27m
125	Auto-RP, Multicast over GRE Tunnels	0h 53m
126	Bootstrap Router (BSR), Bidirectional PIM, Source Specific Multicast (SSM)	0h 40m
127	MSDP, Anycast RP	0h 27m
128	IPv6 Multicast Routing	0h 24m
129	QoS Overview, IntServ QoS, DiffServ QoS, IP Precedence, DSCP, MQC, HQF	0h 41m
130	MQC Classification	0h 44m
131	FIFO, FQ, WFQ, CBWFQ, HQF	0h 50m
132	LLQ	0h 23m
133	WRED	0h 31m
134	Traffic Shaping, Traffic Policing	0h 40m
135	Frame Relay Traffic Shaping (FRTS)	0h 33m
136	RSVP	0h 07m
137	Catalyst 3560 QoS	1h 00m
138	IOS Security Overview, Access Lists (ACLs)	0h 58m
139	Time Based ACLs, Dynamic ACLs	0h 33m
140	Reflexive ACLs	0h 21m
141	TCP Intercept, Content Based Access Control (CBAC)	0h 34m
142	Zone Based Policy Firewall (ZBPF)	1h 09m
143	AAA, Local Authentication, Local Authorization, Role Based CLI Access	0h 43m
144	Port Security, Static CAM Entries, Storm Control, 802.1X Authentication, PACLs, RACLs, VLAN Access Maps (VACLs)	0h 48m
145	DHCP Snooping, Dynamic ARP Inspection (DAI), IP Source Guard	0h 12m
146	Protected Ports, Private VLANs	0h 25m
147	IP Services Overview, HSRP	1h 10m
148	VRRP, GLBP	0h 28m
149	NAT	0h 42m
150	DHCP, DNS	0h 30m
151	NetFlow	0h 09m
152	WCCP, Miscellaneous IP Services	0h 06m
153	System Management Overview, NTP, NTP Authentication	0h 24m
154	SNMP, RMON	0h 38m
155	Syslog, Telnet, SSH, Banners	0h 21m
156	EEM Scripting, Miscellaneous System Management	0h 26m
Total Duration		81h 42m

Slides - Diagrams

Slides - Introduction

Slides - Ethernet Switching

Slides - Advanced Ethernet Switching

Slides - Frame Relay

Slides - PPP

Slides - Transport Bridging

Slides - Redistribution

Slides - IOS Security

Slides - Layer 2 Security

Slides - IP Services

Slides - System Management

0:00:14	The last dynamic routing protocol that we're going to look at here
0:00:16	with IPv6 is BGP.
0:00:20	Now BGP for use with IPv6 is defined in RFC 2545
0:00:26	and that it includes its multiprotocol extensions.
0:00:30	We'll see the logic of this is fairly similar to what we
0:00:33	saw up to this point with using multiprotocol BGP
0:00:36	for the purposes of MPLS routing.
0:00:40	Now one thing that's kind of interesting about how IPv6
0:00:44	works with BGP is that the actual transport of the BGP
0:00:48	session and the advertisement of the network layer reachability information
0:00:53	are technically two unrelated processes.
0:00:57	So what this means is that the routers can peer
0:01:00	with either IPv4 or IPv6 as the Layer 3 protocol
0:01:07	and then independently advertise both IPv4
0:01:11	unicast, IPv6 unicast, IPv4 multicast, IPv6 multicast,
0:01:16	VPNv4, VPNv6 independent of what the transport is.
0:01:23	Now the only functional implication of this is that if the BGP transport
0:01:27	is using IP version 4, we need to make sure
0:01:32	that in the data plane, we are pointing at the correct
0:01:36	next hop value for the actual IPv6 destination.
0:01:42	So we're going to look at this both ways on the command line
0:01:45	where we're establishing the BGP peering using an IPv4
0:01:49	neighbor address, then over this peering we are advertising
0:01:53	IPv6 prefixes, then we'll establish a peering using IPv6
0:01:58	as the transport and advertise IPv6 prefixes
0:02:03	where the actual advertisement of the network layer reachability information
0:02:06	is going to be under the address family IPv6 unicast.
0:02:11	So similar to how we saw before in MPLS
0:02:15	once the transport is up between the neighbors, then we would
0:02:18	activate this particular capability where it is
0:02:22	a negotiated value, so we would want to make sure that
0:02:25	both of the routers on the ends of the peering session
0:02:28	have that particular neighbor activated under the IPv6 unicast address family.
0:02:36	Once we configure the peering, all of the normal BGP rules are going
0:02:39	to apply. This means that for EBGP sessions, we would be using the
0:02:44	autonomous system path for loop prevention.
0:02:46	For IBGP neighbors, we would be using either a full mesh
0:02:50	route reflection or confederation for loop prevention.
0:02:53	The attributes of the BGP updates, things like the
0:02:58	local preference, the AS path, the origin, the Met
0:03:00	those are going to be identical between the IPv4 unicast
0:03:05	network layer reachability information and the IPv6 unicast.
0:03:10	So again, it's one of those cases that if you understand the
0:03:12	IP version 4 counterpart, then you're going to understand
0:03:16	how this works for IPv6
0:03:18	so the main transition point for IPv6 is just to figure out
0:03:23	how the addressing works. Once you can get past that
0:03:26	point, then we can configure basically any of the protocols
0:03:31	with having limited knowledge of their implementation
0:03:34	simply based on us having the understanding of the
0:03:37	IP version 4 counterparts.
0:03:43	So let's take a look at this on the command line
0:03:47	and what we're going to do is configure some peerings
0:03:51	between Router 5 and Router 1
0:03:55	We'll have a peering between Router 1 and Router 5
0:03:59	This is going to be using IPv6 as the transport
0:04:05	then we will peer between Router 1 and Router 6 using
0:04:09	IPv4 as the transport, but still use this to advertise
0:04:14	IPv6 network layer reachability information or basically IPv6 updates.
0:04:20	Now these neighbors could be directly connected
0:04:23	they could be multiple hops away, as long as we have an
0:04:26	IGP that is going to provide the transport, it doesn't really matter
0:04:29	where the neighbors are in the network.
0:04:38	So first let's take a look at Router 5's configuration.
0:04:42	Right now we do have IPv6 reachability
0:04:47	to Router 1's address which is 2001:155:28::1
0:04:58	We also have reachability to their link local address which is
0:05:02	fe80::1
0:05:04	which is reachable out serial 0/0/0
0:05:10	So we could technically do the peering with the link local address
0:05:15	because we do not need the global addresses for
0:05:17	the control plane. If we were doing link local peerings
0:05:21	then that would imply that we have to do it to someone who is directly connected
0:05:25	because link local packets, they cannot be routed between interfaces.
0:05:31	So next let's start the BGP process, we'll say router bgp 5
0:05:37	we have a neighbor that is this address on Router 1
0:05:44	the remote-as is 1
0:05:49	Now without any further configuration beyond this, if we look at the
0:05:53	show run section router bgp
0:05:59	what we would see is that the parameters for this particular neighbor
0:06:03	are actually related to the IP version 4 unicast address family
0:06:09	and not the IPv6 unicast address family
0:06:14	so this means that if we were to go to Router 1 and do an
0:06:17	identical peering on the way back
0:06:20	if we said router bgp 1 neighbor
0:06:23	then we use Router 5's address
0:06:30	who is in remote-as 5
0:06:37	we should eventually see the peering come up
0:06:39	because we already have IP reachability to the neighbors.
0:06:44	If we look at the show ip bgp neighbors
0:06:49	it says that for this particular peer 2001:155:28::5
0:06:56	the neighbor capabilities include the router refresh old and new
0:07:01	and the IPv4 unicast address family.
0:07:07	So it's kind of a strange logic here because we're configuring the
0:07:10	control plane transport using TCP over IPv6
0:07:18	but then we're actually using this to advertise IPv4 routes.
0:07:24	So if I were to go to Router 5
0:07:26	I can now go under the BGP process and say
0:07:30	network 155.28.5.0
0:07:36	with a mask of /24 so a normal advertisement into
0:07:41	IPv4 BGP
0:07:44	If we look at the result of this on Router 1 and
0:07:46	look at the show ip bgp
0:07:48	we see that we're learning the prefix in from Router 5
0:07:56	the problem though is that in the update, the next hop value
0:08:00	is not properly encoded
0:08:02	because it's going over the IPv6 transport and the IPv6
0:08:08	address is not compatible with the IP version 4 address.
0:08:12	So what I could do here I could do kind of a manual
0:08:15	hack in order to fix this. I could create a route map that
0:08:19	says IPv4 BGP in from Router 5
0:08:25	that says set the IP next hop to 155.28.0.5
0:08:31	then under the BGP process for this particular neighbor
0:08:37	who has the IPv6 address
0:08:39	I'm going to apply the route map IPV4 BGP in from Router 5
0:08:48	inbound.
0:08:56	So now if we look at the show ip bgp
0:09:00	we should see that the next hop value is going to change
0:09:04	to the value of the connected interface
0:09:07	so now the route map has been applied.
0:09:10	Now we can see the prefix is installed as a best path
0:09:13	because we do have a route to the next hop.
0:09:16	If we look at the show ip route bgp
0:09:19	we can see that that destination is installed in the routing table.
0:09:22	If we send packets to it ping 155.28.5.5
0:09:27	Router 1 has transport to it.
0:09:31	So it's kind of an odd design here because we're using
0:09:33	again, the same TCP session because the key point to
0:09:38	remember is that the upper layer protocols are not
0:09:41	changing, so things like http for web browsing
0:09:47	or telnet, any standardized TCP application it does not
0:09:52	need to change to run over IPv6 versus IPv4
0:09:58	so it's the same type of logic with BGP here.
0:10:01	We're using TCP for the transport, but TCP
0:10:06	is then being encapsulated inside IPv6 as opposed to IPv4
0:10:12	because BGP is really an application, not necessarily
0:10:16	a routing protocol per se.
0:10:19	It's an application with two jobs: to advertise a prefix
0:10:23	and a next hop value associated with the prefix.
0:10:32	But typically, you would not do this in a design
0:10:35	it doesn't really make sense to use the IPv6 as transport
0:10:38	and then advertise the IPv4 routes over it.
0:10:42	Eventually maybe 10 or 20 years down the road
0:10:44	where the vast majority of the networks are running
0:10:47	IPv6 and IPv4 is then considered legacy
0:10:51	this is kind of like the reverse transition mechanism
0:10:55	where now we're using the IPv6 control plane to advertise the
0:11:00	legacy IPv4 protocols
0:11:04	and we could also do it in the reverse direction.
0:11:08	So now let's go under the BGP process
0:11:10	and the normal configuration here would be to go to the
0:11:14	address family IPv6 unicast
0:11:18	and specify that for this particular neighbor
0:11:22	I want to activate that address family.
0:11:27	So it's basically saying I want to exchange IPv6
0:11:31	prefixes with that particular neighbor over BGP.
0:11:35	Router 5 is going to say the same thing
0:11:39	address family ipv6 unicast
0:11:43	the neighbor is Router 1
0:11:48	and I want to activate them.
0:12:02	So let's look at the full configuration of both Router 1
0:12:05	and 5 let's say show run section router bgp
0:12:11	Router 1 we'll do the same thing show run section router bgp
0:12:15	On Router 5 we have the neighbor
0:12:18	that is Router 1
0:12:23	we're using the IPv6 address of Router 1
0:12:27	then we're saying in addition to the IPv4 unicast address family
0:12:31	which is on by default, I also want to run IPv6 unicast.
0:12:38	So now if we look at the show ip bgp neighbors
0:12:49	it says we have a new address family capability
0:12:52	which includes IPv4 unicast and now IPv6 unicast as well.
0:13:00	So from this point on any advertisements or attribute
0:13:03	modification for IPv6 specific routes, that would then go
0:13:08	under the IPv6 unicast address family.
0:13:12	So if Router 5 wanted to go to the BGP process
0:13:20	and under address family IPv6 unicast
0:13:25	specify that we're going to do a network advertisement
0:13:29	if we show ipv6 route connected
0:13:34	we'll say advertise Fast Ethernet 0/1
0:13:38	so that exact prefix is going to get advertised into
0:13:41	IPv6 BGP
0:13:49	then on Router 1 when we look at the show ipv6 route bgp
0:13:57	or show ipv6 bgp
0:14:02	and you'll see in some versions they take the syntax
0:14:05	like this, some versions you'll have to say
0:14:09	show bgp, then followed by the address family and the
0:14:12	sub address family identifier similar to what we
0:14:14	were doing before with MPLS.
0:14:17	So if we say here show bgp ipv6 unicast
0:14:21	this is the equivalent of the show ip bgp
0:14:25	If I said show bgp ipv6 unicast summary
0:14:31	it shows we have the peering that's going over to Router 5
0:14:38	If we show bgp ipv6 unicast and then this particular prefix
0:14:46	we see we have the next hop value
0:14:49	it says it's being learned from -- or actually it's
0:14:52	via this link local address
0:14:56	it's being learned from this particular neighbor
0:14:58	they have the router ID 150.28.5.5
0:15:01	Its origin was IGP, so it means it was coming from the
0:15:05	network statement.
0:15:06	Met is 0, local preference is 100, it's an external route
0:15:10	and this is the best path.
0:15:17	So from this point on the rest of the rules of BGP are
0:15:19	going to be the same.
0:15:21	The key is that you can do the peering independent from
0:15:25	the address family.
0:15:27	So now on Router 1, we're doing the peering
0:15:31	via IPv6
0:15:34	and we're also doing advertisements of IPv6 networks.
0:15:45	Now between Router 1 and Router 6
0:15:48	we're going to do an IPv4 BGP peering
0:15:53	but then use this to advertise the IPv6 address family.
0:15:59	So it's the opposite of what I did between Router 1
0:16:01	and Router 5
0:16:05	so on Router 1 let's go to bgp 1
0:16:08	we'll specify there's a neighbor 155.28.146.6
0:16:12	who is in as 6
0:16:19	Router 6 is going to say the same thing, so there's a
0:16:22	neighbor that is Router 1
0:16:24	who is in as 1
0:16:28	but now under the address family ipv6 unicast
0:16:32	I'm going to activate this neighbor.
0:16:39	Router 1 is going to do the same thing.
0:16:42	So address family IPv6 unicast
0:16:54	and if we did not want to run the IPv4 unicast address family
0:16:58	between the neighbors, we could either globally under the
0:17:02	process say no bgp default ipv4 unicast
0:17:12	where this basically says do not automatically negotiate
0:17:16	that particular address family identifier
0:17:20	or we could specifically go under the address family IPv4
0:17:23	unicast and say for this neighbor I do not want to activate them.
0:17:49	So Router 6 is going to say the same thing
0:17:51	no neighbor Router 1's address activate.
0:17:55	Once the peering comes back up if we look at the show bgp neighbors
0:18:01	or show ip bgp neighbors
0:18:07	we should see that the control plane transport
0:18:11	is TCP running over IP version 4
0:18:17	but the information that the neighbors are going to advertise
0:18:21	is IPv6
0:18:25	so what I need to say here then is show bgp ipv6 unicast neighbors
0:18:35	which again is kind of odd because it's an IPv4 address
0:18:39	that is the IPv6 unicast neighbor where we have the
0:18:43	IPv6 unicast address family advertised and received
0:18:50	also this version supports the new autonomous system numbers
0:18:54	which are the 4-byte AS values.
0:18:56	If we now look at the show bgp ipv6 unicast
0:19:02	we see that now we're learning the route towards
0:19:04	Router 5's BGP route, but the next hop value points to an
0:19:10	IPv4 address.
0:19:18	So just like I had to do previously with the IPv4
0:19:23	address family over the IPv6 transport
0:19:27	on Router 6 as I receive the update in from Router 1
0:19:31	I'm going to have to change the next hop value
0:19:34	so it points to my legitimate IPv6 neighbor
0:19:39	so specifically this neighbor's address if we look at the
0:19:42	show ipv6 neighbor
0:19:44	I want it to point at either this address of Router 1
0:19:48	or the link local address of Router 1
0:19:51	either of them are going to be fine because it's essentially going to
0:19:53	point towards the same neighbor.
0:19:58	Just the problem is now that when we look at the detail
0:20:00	for this route, we cannot use it for best path selection
0:20:06	because it says this next hop is inaccessible.
0:20:10	Basically this is just an invalid value that's there.
0:20:14	So this has to point to an IPv6 address, not to an
0:20:17	IPv4 address.
0:20:21	There is one exception to this which is a feature
0:20:24	that is known as 6PE
0:20:35	and 6PE is basically a special encoding for multiprotocol BGP
0:20:41	updates that can be used to advertise IPv6
0:20:46	routes over the VPNv4 address family in MPLS.
0:20:53	So there's really two points that are kind of interesting
0:20:55	about how this works
0:20:58	that the next hop value
0:21:03	it says that the multiprotocol BGP creates a BGP update
0:21:09	including the reach network layer reachability information
0:21:12	that is AFI 2 SAFI 4
0:21:18	which is an IPv6 labeled route
0:21:23	which it gives them not only the prefix, but it gives them an
0:21:28	MPLS label for it and points the next hop to an IPv4
0:21:33	neighbor, so it's kind of a hack on the process and
0:21:38	it's kind of interesting to read through this.
0:21:41	Basically this is the transition mechanism for service providers
0:21:44	that are running IP version 4 based MPLS
0:21:48	for them to support IPv6 transport over this particular network
0:21:54	because the idea is that in the service provider core
0:21:57	we don't want to have to enable -- we don't want to have to
0:22:00	enable IPv6
0:22:02	so the core is already running MPLS and IPv4 transport.
0:22:07	So between these two PEs that are running IPv6
0:22:12	they're exchanging the IPv6 routes
0:22:15	but the next hop value points to an IPv4 destination
0:22:21	that we can use an MPLS transport label
0:22:24	in order to reach.
0:22:26	So we're basically tunneling IPv6 over MPLS by using
0:22:30	an IPv4 next hop.
0:22:34	So this feature is definitely not going to be within the scope of
0:22:37	the routing and switching exam, but it is kind of interesting to know
0:22:40	how this works because this is one of the transition mechanisms
0:22:43	that's moving as closer to having ubiquitous IPv6 support.
0:22:52	So again, the problem I'm running into now here with Router 6
0:22:55	is that it's receiving the update in, but it's coming in with an
0:22:59	invalid next hop value, so what I need to do now is
0:23:02	basically change this so it points at Router 1
0:23:06	so I'll have a route map that says from Router 1
0:23:12	that sets the IPv6 next hop value to Router 1's address
0:23:21	then under BGP 6
0:23:24	address family IPv6 unicast
0:23:28	the neighbor's address again is the IPv4 address of Router 1
0:23:38	and I'm applying the route map from Router 1
0:23:44	inbound.
0:23:50	Now if I ask for route refresh if I say clear bgp
0:23:54	ipv6 unicast inbound
0:24:00	for * in
0:24:03	then show bgp ipv6 unicast for this particular prefix
0:24:12	Now we see the next hop value has been changed to
0:24:15	the IPv6 address of Router 1
0:24:17	which means ultimately I can perform route recursion on this
0:24:21	and then install it into the routing table.
0:24:24	So if I show ipv6 route bgp
0:24:29	now the route is installed and I should be able to
0:24:35	send traffic to this destination.
0:24:47	Now whether I can actually reach this or not is going to depend
0:24:50	if Router 5 has a route back because right now
0:24:53	Router 6 is not advertising anything so if I were to go to
0:24:56	Router 5 let's look at the debug ipv6 packets
0:25:01	I want to know at least is Router 5 receiving the packets
0:25:06	in from 6
0:25:12	which it is.
0:25:14	So the packets got from 6 to 5, but then 5 is doing a
0:25:19	routing lookup and it doesn't have a route back to the source.
0:25:22	So that's fine, that's not really Router 6's problem
0:25:25	that's Router 5's problem because it doesn't have that
0:25:27	particular route back.
0:25:29	But we can tell at least one way the traffic is getting there.
0:25:38	So again, let's look at our final configurations for this on Router 1
0:25:42	show run section router bgp
0:25:47	We have an IPv6 neighbor that we are running the IPv6
0:25:52	address family with,
0:25:54	but then we also have an IPv4 neighbor that we're running
0:25:57	the IPv6 address family with.
0:26:02	So the key point being here that the transport of BGP
0:26:05	is independent of the address families that it is advertising.

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CCIE R&S Advanced Technologies Class v4.5
Title:	CCIE R&S Advanced Technologies Class v4.5
Duration:	81h 42m
The CCIE Routing & Switching Advanced Technologies Class is the first step in understanding CCIE level technologies and is a companion to the Advanced Technologies Lab Workbook. Each technology you need to know for the CCIE Routing & Switching lab will be described in detail using an instructor led hands on demonstration. The class consists of over 80 hours of in depth explanations and examples.
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MP-BGP for IPv6

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