HANK at taunivm.tau.ac.il
Fri Aug 18 08:34:21 UTC 1995
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.
>> >> Simon
>> >CIDR 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 at mci.net'.
Starting Friday morning 11 August, please make sure that all new
and updated route objects contain the new 'advisory' string.
More information about the NANOG