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New Member

IPv6 Route Summarization

Hi everybody,

My ISP gave me a /56 block of IPv6 adresses.
For our network, we split this block into /64 subnets.

The problem is:

For each of our subnets (/64), my ISP has to add a route on their router. I asked them if they could put a summarized route (the /56 block) but they answered that is it not possible.

Is it true ?

The router is a Cisco 1841 with "c1841-adventerprisek9-mz.150-1.M4.3" IOS version.

Thanks,

Armand.

  • IPv6 Integration and Transition
Everyone's tags (3)
8 REPLIES
Silver

IPv6 Route Summarization

What routing protocol are you running as the summarization configurtaion is different for each protocol...

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Posted by WebUser Neeraj Jagga from Cisco Support Community App

New Member

IPv6 Route Summarization

There are static routes..
Is it possible to summarize them ?

Re: IPv6 Route Summarization

Yes summarization is perfectly possible. There shouldnt be any issue for ISP as it will make their work simpler as well.

e.g

2001:100:100:101::/64

2001:100:100:102::/64

2001:100:100:103::/64

2001:100:100:104::/64

2001:100:100:105::/64

I.e First three blocks are same so if we convert 4th block to binary, we have,

0000 0001 0000 0001

0000 0001 0000 0010

0000 0001 0000 0011

0000 0001 0000 0100

0000 0001 0000 0101

------------------------------

0000 0001 0000 0^^^

Summary for those 5 routes will be : 2001:100:100:101::/61

All they need to do is "ipv6 route 2001:100:100:101::/61 fa0/0"

Thanks,

Nandan Mathure

New Member

Re: IPv6 Route Summarization

Thanks for your answer, I clearly understand the principle =)

But my ISP still says that he can not add IPv6 route with a prefix less than /64... (on 1841)

New Member

Re: IPv6 Route Summarization

The 1841 is your CPE equipment? The summarization should happen at the PE router, so I wouldn't see it as a problem unless the misunderstand the request. Hurricane Electric summarizes my /48 prefix just fine, regardless of what router I use on my end of the link.

Sent from Cisco Technical Support iPad App

New Member

Re: IPv6 Route Summarization

Yes, it's the CPE.

New Member

Re: IPv6 Route Summarization

Do you use a routing protocol to advertise your prefix(es) upstream to your provider, or is that routing done via static routes?

Sent from Cisco Technical Support iPad App

New Member

Re: IPv6 Route Summarization

That routing is done via static routes (on the CPE)

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