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Webcast-Catalyst9k
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AS NUMBER ISSUE

i have an as number in use in within our network that has its own internet feed.please is it possible to use the same AS number in a new network with seperate internet feed.

3 REPLIES
Hall of Fame Super Gold

Re: AS NUMBER ISSUE

As long you don't try to use it to connect the internet, there is no problem.

Re: AS NUMBER ISSUE

What you are saying is what I would expect as ASN's group administrative networks together, ie both network belong to you, so both should have the same ASN. You should peer to both providers with the same ASN and if these networks are connected, which I assume they are, then you have yourself a resilient setup now. If not then only advertise the networks that are reachable each peering session.

Hall of Fame Super Silver

Re: AS NUMBER ISSUE

Hello Olankule,

if this AS number is public (in range 1-64511) your company has received by regional registry that is RIPE for europe.

until you advertise public ip address blocks registred with RIPE you need to use that ASN in all your internet connections.

some issues can arise if there are no direct connections between the two sites.

However,

on your routers

neigh ISP.ipaddress allowas-in N

this allows intercommunication between sites using the same ASN (it allows your router to accept BGP prefixes where your ASN already is present up to N times in the AS path attribute)

It is better to find a way to communicate for the two sites even with an EoMPLS pipe

Hope to help

Giuseppe

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