Re: "no ip bgp default ipv4-unicast"

I assume you are talking about the BGP command "no bgp default ipv4-unicast" first of all. Secondly, without this command any neighbor relationship you bring up is ASSUMED to be IPv4 right out of the box. So if you don't have address-families in use at all and you type "neighbor 1.1.1.1 remote-as 100" you are bringing up an IPv4 peering to carry IPv4 prefix information. The "no bgp default ipv4-unicast" command disables that feature. Sure, you could go into the address-family and de-activate the neighbor, but with this command option you don't have to have the IPv4 address-family at all in the first place.

HTH

Regards,
Joe Astorino, CCIE #24347

"He not busy being born is busy dying" -- Dylan

----- Original Message -----
From: "Gaurav Thukral" <pearlgaurav_at_gmail.com>
To: "Group study" <ccielab_at_groupstudy.com>
Sent: Monday, May 24, 2010 12:25:51 PM GMT -05:00 US/Canada Eastern
Subject: "no ip bgp default ipv4-unicast"

Hi Experts,

I have one doubt regarding "no ip bgp default ipv4-unicast".

This command is mentioned in most of the books as required to disable IPv4
BGP neighborship between router reflector client and router reflector, when
we want to use router reflector only to reflect VPNv4 routes.

But we can disable Ipv4 BGP neighborship by using "no neighbor <> activate"
under address-family ipv4.

So my question is why at all we need "no ip bgp default ipv4-unicast"
command under router bgp config ?

-- 
Regards, 
*Gaurav Thukral* 
Blogs and organic groups at http://www.ccie.net