IPv6 Aggregation

From: gladston@br.ibm.com
Date: Fri Aug 12 2005 - 14:09:50 GMT-3


Hi,

This example seems to be wrong. What do you think?

====================================================
For example, an NLA provider with the address space of 2001:0420:0001::/48 can allocate the following address space:

   
      2001:0420:0001:1:/48
   
      2001:0420:0001:2:/48
   
      2001:0420:0001:3:/48

quoted from:
Configuring IPv6 with Cisco IOS
by Sam Brown
===================================================

The /48 for the customers...it is not right.
It should be other than /48 (for example /64 or /52) to the customer, otherwise it overlaps.
Agree?

The book is giving an example of TLA, sub-TLA, and NLA prefix allocation.

TLA-1 provides this prefix to sub-TLA1:
        2001:0420::/35 - sub-TLA1

sub-TLA-1 provides this prefix to NLA-x:
        2001:0428:0001::/48

NLA-x provides these prefixes to its customers:

customer 1 2001:0420:0001:1:/48
customer 2 2001:0420:0001:2:/48

Test 1:

Rack2R3(config)#int lo 1001
Rack2R3(config-if)#ipv6 address 2001:0420:0001:1::3/48

Rack2R3(config-if)#int lo 1002
Rack2R3(config-if)#ipv6 address 2001:0420:0001:2::3/48
% Prefix 2001:420:1:2::3/48 overlaps with another prefix

Test 2:
On this test, R5 is the NLA and R2/R3 are customers.

Rack2R3#

interface Loopback1001
 no ip address
 ipv6 address 2001:420:1:1::3/48
 ipv6 address 2001:420:1:2::3/48
 ipv6 rip RIPng enable

Rack2R3#

interface Loopback1001
 no ip address
 ipv6 address 2001:420:1:3::2/48
 ipv6 rip RIPng enable

Rack2R5#sh ipv6 route rip | b 2001:420:1:
R 2001:420:1::/48 [120/2]
     via FE80::2, Serial0/0
     via FE80::3, Serial0/0

Rack2R5#pi 2001:0420:0001:3::2

debug:

Rack2R3#
Aug 12 10:41:20: IPV6: source 2001:148:5:235::5 (Serial1/0.235)
Aug 12 10:41:20: dest 2001:420:1:3::2 (Loopback1001)

Rack2R2#
Aug 12 10:41:22: IPV6: source 2001:148:5:235::5 (Serial0/0.235)
Aug 12 10:41:22: dest 2001:420:1:3::2

On the other hand, using prefix /52 to each customer it works fine:

R 2001:420:1:2000::/52 [120/2]
     via FE80::2, Serial0/0
R 2001:420:1:3000::/52 [120/2]
     via FE80::3, Serial0/0



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