nanog mailing list archives
Re: CIDR FAQ
From: Hank Nussbacher <HANK () taunivm tau ac il>
Date: Fri, 18 Aug 95 08:34:21 IST
On Thu, 17 Aug 1995 17:01:14 -0700 (MST) you said:
On Thu, 17 Aug 1995 00:30:19 +0200 (MET DST) you said:Simon Poole wrote:Yakov, if you have data that CIDR is -not- working for new allocations please present it here. SimonCIDR doesn't work as it should. We had to inject all of the more specifics of 194.45/16 cause Sprintlink isn't able to handle CIDR routes correctly.Can someone explain this a bit more? This sounds like a showstopper for CIDR.I have noticed some similar problems. MCI routing breaks if you provide them with an identical path at multiple interconnects if it is advertised to them at equal cost, hence they always like to see MEDs.
In regards, a recent announcement (8/11): To All Maintainers of Data in the MCI Routing Registry, Until very recently, ANS's routers have been unable to support the MULTI_EXIT_DISCRIMINATOR (MED) attribute of BGP4. The result of this was that if an Autonomous System (AS) peered with ANS in more than one place, static configuration was required to specify which peer is the preferred exit point from ANS. This need for static configuration was satisfied with the 'advisory: AS690' attribute. ANS has now implemented MEDs in their routers and has already tested it with a few ASs. They have told us that they are willing to turn on MEDs with AS3561 on Tuesday 15 August. This greatly simplifies the 'advisory' attribute needed in the registry. For example, if your current 'advisory' attribute looks like: advisory: AS690 1:3561(11) 2:3561(144) 3:3561(27) 4:3561(147) 5:3561(218) it can now be reduced to: advisory: AS690 1:3561 We do not know which other providers, if any, have arranged to send MEDs to ANS. So, if some of the networks you maintain in the RR are multi-homed to provider(s) which also peer with ANS in more than one place, you would need to talk directly to the other provider(s) to see if the 'advisory' string should change. An example of an 'advisory' attribute for a network that is homed to both MCI and Alternet, with primary service through MCI, and assuming that ANS has not enabled MEDs with AS701, is: advisory: AS690 1:3561 2:701(147) 3:701(144) The RR Users Guide will be updated with this information; it will not contain any more information than this e-mail message. The most recent version of the Users Guide is always available from "ftp://ftp.mci.net/pub/rr/docs/mci-user.txt" (a PostScript version is also available with an extension of '.ps'). MCI is volunteering to change 'advisory' attributes in existing route objects in the MCI RR to the new syntax; ASs other than 3561 *will* be preserved, so the semantic of the 'advisory' will *not* change. We will make this change on Friday morning 11 August. If you have any questions or concerns about this, please tell us before Friday morning by sending a message to 'rr-types () mci net'. Starting Friday morning 11 August, please make sure that all new and updated route objects contain the new 'advisory' string. Thank You. /jws
Dave
Hank
Current thread:
- Re: CIDR FAQ, (continued)
- Re: CIDR FAQ Curtis Villamizar (Aug 17)
- Re: CIDR FAQ Arnold Nipper (Aug 18)
- Re: CIDR FAQ Curtis Villamizar (Aug 17)
- Re: CIDR FAQ Sean Doran (Aug 17)
- Re: CIDR FAQ Sean Doran (Aug 17)
- Re: CIDR FAQ Sean Doran (Aug 17)
- Re: CIDR FAQ Dave Siegel (Aug 17)
- Re: CIDR FAQ Sean Doran (Aug 17)
- Re: CIDR FAQ Hank Nussbacher (Aug 17)
- Re: CIDR FAQ Dorian Rysling Kim (Aug 17)
- Re: CIDR FAQ Elise Gerich (Aug 18)
- Re: CIDR FAQ Dorian Rysling Kim (Aug 17)
- Re: CIDR FAQ Hank Nussbacher (Aug 17)
- Re: CIDR FAQ Guy T Almes (Aug 18)
- Re: CIDR FAQ Kent W. England (Aug 18)
- Re: CIDR FAQ Yakov Rekhter (Aug 18)
- Re: CIDR FAQ Ross Veach (Aug 18)
- Re: CIDR FAQ Ross Veach (Aug 18)
- Re: CIDR FAQ Dave Siegel (Aug 18)