Static IPv6 Routes ccie security training institute in delhi gurgaon

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IPv6 supports the configuration of static routes with similar syntax compared to the ip
route command used to configured IPv4 static routes. The syntax of the ipv6 route command
matches the ip route command, other than that the IPv6 destination is represented
as prefix/length, and any next-hop IP address is an IPv6 address, of course. The generic
syntax is
ipv6 route prefix/length {outgoing-interface [next-hop-address] | next-hopaddress}
[admin-distance] [tag tag-value]
The parameters use the same concepts as the same parameters used for IPv4. However,
with IPv6, a few interesting differences exist. First, when using the next-hop IP address,
you can use any address on the neighboring router, including the neighbor’s link local IPv6
address. Second, if using a link local address as the next-hop address, then you must configure
both the outgoing interface and the link local address.
Example 17-10 shows such a case, with a static route configured on Router R3 in Figure
17-4. R3 adds a static route for R1’s LAN prefix, 2000::/64, using R2 as next hop, specifically
R2’s F0/1 link local address as next hop.
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R1 R3
R2
2000::/64
F0/0
ipv6 route 2000::/64 F0/0 FE80::213:19FF:FE78::5005
S0/0/1 F0/1
Figure 17-4 Static IPv6 Route on Router R3
Example 17-10 Static Route on R3, with Link Local Next-Hop Address
R3# conf t
Enter configuration commands, one per line. End with CNTL/Z.
R3(config)# ipv6 route 2000::/64 FE80::213:19FF:FE7B:5005
% Interface has to be specified for a link-local nexthop
R3(config)# ipv6 route 2000::/64 f0/0 FE80::213:19FF:FE7B:5005
R3(config)# ^Z
R3# show ipv6 route
IPv6 Routing Table - Default - 7 entries
Codes: C - Connected, L - Local, S - Static, U - Per-user Static route
B - BGP, M - MIPv6, R - RIP, I1 - ISIS L1
I2 - ISIS L2, IA - ISIS interarea, IS - ISIS summary, D - EIGRP
EX - EIGRP external
O - OSPF Intra, OI - OSPF Inter, OE1 - OSPF ext 1, OE2 - OSPF ext 2
ON1 - OSPF NSSA ext 1, ON2 - OSPF NSSA ext 2
S 2000::/64 [1/0]
via FE80::213:19FF:FE7B:5005, FastEthernet0/0
C 2000:0:0:2::/64 [0/0]
via FastEthernet0/0, directly connected
L 2000:0:0:2::3/128 [0/0]
via FastEthernet0/0, receive
C 2000:0:0:3::/64 [0/0]
via FastEthernet0/1, directly connected
L 2000::3:213:19FF:FE7B:6589/128 [0/0]
via FastEthernet0/1, receive
OE2 2000:0:0:4::/64 [110/200]
via FE80::213:19FF:FE7B:5005, FastEthernet0/0
L FF00::/8 [0/0]
via Null0, receive
R3# show ipv6 route 2000::/64
Routing entry for 2000::/64
Known via “static”, distance 1, metric 0
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Chapter 17: IPv6 Routing Protocols and Redistribution 601
Backup from “ospf 1 [110]”
Route count is 1/1, share count 0
Routing paths:
FE80::213:19FF:FE7B:5005, FastEthernet0/0
Last updated 00:11:50 ago
The example shows a static route that uses a multiaccess interface as the outgoing interface,
so using both the outgoing interface (F0/0) and the next-hop address in the ipv6
route command prevents ambiguity. Also, note that IPv6 routers do not actually have a
route that matches the neighbor’s link local address. As a result, the ipv6 route command
must supply the outgoing interface as well, so the local router (R3 in this case) knows on
which interface to use NDP to discover how to reach this neighboring IPv6 address. The
example shows an attempt to configure the ipv6 route command with only R2’s next-hop
link local address, but R3 rejects the command. When both the outgoing interface (F0/0)
has been listed, plus R2’s link local address as next hop, R3 accepts the command and adds
this static route to its IPv6 routing table.
Finally, the output of the show ipv6 route 2000::/64 command at the end of the example
lists some information not seen in the equivalent IPv4 command. The output reveals some
insight into the operation of the routing table manager (RTM), which chooses the best
route for a prefix among many sources. In this case, the static route for 2000::/64 used a
default administrative distance of 1. The routers in this design were also still configured as
they were at the end of Example 17-9, with RIP on the left of the figure, OSPF on the
right, and redistribution between the two. So, R3 still has an OSPF route for 2000::/64,
with default administrative distance 110. The output of this command lists not only the
static route, but also the backup route, with a worse administrative distance, in this case
the OSPF-learned route. When configuring a floating static route–a static route with a
high administrative distance so that the route will not be used until the IGP routes have all
failed–this command can be useful to confirm that this backup route is known to IOS.