nanog mailing list archives

Re: [NANOG] RFC1918 conformance


From: "Alex P. Rudnev" <alex () Relcom EU net>
Date: Thu, 13 Feb 1997 13:47:24 +0300 (MSK)

On Wed, 12 Feb 1997, Dana Hudes wrote:

Gated allows you to specify the ospf router id. AS others have mentioned
so does Bay.  Out of curiousity, is anyone running anything other than
I know it well (really we have few gated-based routers there). Let me to 
point my mind - it may be usefull to have short reserved address space in 
the beginning (net 1.0.0.0) and the end (223.255.0.0/16 or simular) 
address space. CISCO's router-id was used as amazing example _why it mey 
be usefull_.

Cisco, Bay or something with GateD (which includes IBM 6611, Netstat
Gigarouter and a few others which escape recall at the moment) for
routing in the Internet (not private nets; I know that Mitsubishi
Electric Corp of America uses IBM 6611 and some 2210, all with backlevel 
software).

Dana


On Wed, 12 Feb 1997, Alex P. Rudnev wrote:

Date: Wed, 12 Feb 1997 13:58:30 +0300 (MSK)
From: "Alex P. Rudnev" <alex () Relcom EU net>
To: "Jeffrey C. Ollie" <jeff () ollie clive ia us>
Cc: nanog () merit edu
Subject: Re: [NANOG] RFC1918 conformance 

For example. I have a lot of CISCO routers with OSPF protocol. Thnis 
crazy IOS use highest loopback interface address as router-ID address; I 
use loopbacks to install load balancing etc. and I can't prevent 
loopbacks from being equal on the different routers. That's why I hardly 
need some IP addresses for 'Loopback 98' interface to use it as 
router-ID; and this have to be higher than any user's addresses. I use 
233.255.254.0/24 for this purposes, but it's not reserved address.

This is one, simple, example why it's nessesary to reserve some short 
address space in the begin and in the end of total addresses.

No, that's an example of a poorly designed protocol
implementation. One ought to be able to specify an arbitrary router id
for OSPF (heh - even Bay routers can do that :) rather that relying on
such an odd algorithm. I was so surprised by this that I just had to go
look it up:
I know _it's example of poorly designet software_. But I'd like to note 
it's not only example when it's usefull to have some addresses _greater 
than any other_ for private usage.

<http://www.cisco.com/univercd/data/doc/software/11_2/cnp1/5ciprout.htm#REF38888>

The equivalent Bay reference:

<http://support.baynetworks.com/Library/tpubs/content/114065A/J_55.HTM#HEADING55-6>

Yes, I was more surprised when they (cisco) did not implement something 
like _ip ospf router-id A.B.C.D_ into new IOS 11.2. We have 3 or 4 
routing troubles due to this IOS property (and it always looked as 
_hidden bug_ because it is si,ular to the delayed bomb - it explodes 1 
week below some mistake was made in the config files -:)).




Aleksei Roudnev, Network Operations Center, Relcom, Moscow
(+7 095) 194-19-95 (Network Operations Center Hot Line),(+7 095) 239-10-10, N 13729 (pager)
(+7 095) 196-72-12 (Support), (+7 095) 194-33-28 (Fax)

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