4 byte ASN Limitaiton

[Muhammad Kashif Siddiqui]

I am having 3845 Router where we are establishing BGP Session with my Service Provider. I am having 4 Byte public AS (say 201200) whose Doted Notation as per calculation is (3.4592). My current IOS is 12.4 (24) T5. Now when I am configuring that the only option which is available with me is in ASDOT format and I cannot put my AS in ASPLAIN format. I found one document which give me a bit help but still I have few question with regards to it.

Here is the Document:

http://www.cisco.com/c/en/us/products/collateral/ios-nx-os-software/border-gateway-protocol-bgp/white_paper_c11_516829.html

Questions:

1. what the best practice from Cisco (AS in dot-format? or AS plain-format?)

2. IOS upgrade is required to configure the AS in the plain format? Which IOS supports ASDOT along with ASPLAIN ?

3. Are there any limitations when using AS dot-format (like regular expressions support?)

Regards

[Vasilii Mikhailovskii]

Hello.

1. I believe the best practice is to be consistent through all your network :)

2.

Looks like 12.4(24)T does not support asnotation command.

I checked 15.0(1)M9 and it supports it.

3. After you change asnotation, you need to hard-restart all BGP peers - this might be a show-stopper.