nanog mailing list archives
Re: iBGP next hop and multi-access media
From: "John M. Brown" <john () chagresventures com>
Date: Tue, 8 Oct 2002 07:02:41 -0700
Please do NOT confuse PHYSICAL plumbing with LOGICAL plumbing. Based on your description, router A and B ARE NOT on the same broadcast domain, with respect to 172.16.16/24. THey are on the same broadcast domain as 10.10.10.0/30 But thats it. In otherwords, No it is NOT technically possible for B to tell A that what it wants is on the same media. Welcome to one of the few down falls of loading up multiple nets on the same physical interface. On Sun, Oct 06, 2002 at 04:25:00PM -0400, Ralph Doncaster wrote:
A and B are connected via the same multi-access media. It is technically possible for B to tell A "you can reach 172.16.16.0/24 on the same media that you receive this update on". However what people seem to be saying is that there is no dynamic routing protocol that implements this. Ralph Doncaster principal, IStop.com On Sun, 6 Oct 2002, Stephen J. Wilcox wrote:I dont understand this.. A wants to get to a network which it [thinks it] is not connected to, the only route is via B. therefore you must advertise the route from B with next hop B the only possible way (at least in ethernet IP) that A can send direct onto the ethernet segment is if it is connected to the other (172.16) network and if youre not willing to do that then your solution is not possible Steve On Sun, 6 Oct 2002, Ralph Doncaster wrote:Background: Router A and B are connected via a common ethernet segment 1. Router A uses 10.10.10.1/30, and Router B uses 10.10.10.2/30. Router B also has another subnet configured for ethernet segment 1; 172.16.16.0/24. When I setup a situation like the above, with Router B advertising the 172.16.16.0/24 to router A, router A sees a next hop of 10.10.10.2. This is not good since packets from A going to the 172.16.16 subnet get sent to Router B, which then ARPs the desitnation, instead of just being ARPed by router A. I don't want to turn on ICMP redirects on B since they're insecure and ugly. I've also made sure I'm not using next-hop self. Is there a way to make this work? Ralph Doncaster principal, IStop.com
Current thread:
- Re: iBGP next hop and multi-access media, (continued)
- Re: iBGP next hop and multi-access media Pete Templin (Oct 07)
- Re: iBGP next hop and multi-access media John M. Brown (Oct 08)
- Re: iBGP next hop and multi-access media Ralph Doncaster (Oct 06)
- Re: iBGP next hop and multi-access media Mark Kent (Oct 06)
- Re: iBGP next hop and multi-access media Gregory Urban (Oct 08)
- Re: iBGP next hop and multi-access media Ralph Doncaster (Oct 06)
- Re: iBGP next hop and multi-access media Clayton Fiske (Oct 06)
- Re: iBGP next hop and multi-access media Ralph Doncaster (Oct 07)
- Re: iBGP next hop and multi-access media Stephen J. Wilcox (Oct 06)
- Re: iBGP next hop and multi-access media alex (Oct 07)
- Re: iBGP next hop and multi-access media John M. Brown (Oct 08)
- Re: iBGP next hop and multi-access media Clayton Fiske (Oct 06)
- RE: iBGP next hop and multi-access media Charles Youse (Oct 06)
- RE: iBGP next hop and multi-access media Martin, Christian (Oct 06)