gigabit router (was Re: Getting a "portable" /19 or /20)

alex at yuriev.com alex at yuriev.com
Wed Apr 11 22:39:18 UTC 2001


> CEF is not the only mechanism to implement distributed forwarding
> (within or without Cisco for that matter), and to say that distributed
> forwarding is faulty because of software complexities of one
> manufacturer, whose code base is built upon on a monolithic core (to use
> operating system would lower what it means to actually be a operating
> system) is to generalize all failures to a distributed architecture
> where the fault does not _always_ lie.

CEF and dCEF periodically break on Cisco. They break in the most interesting
ways - the debugging indicates that the packets are going one way when they
in reality are going the other way. Without CEF or dCEF Cisco's are useless
for the amount of traffic that I am interested in.

Juniper is very interesting. The only problem is a gazillion strange things
that it tries doing. Juniper's BGP has very intereting bugs in
confederations which I have discovered on the day #1 of putting one of them
into production. That bug is still not fixed. Since confederations are very
widely used, and no one else found this bug, and yet we have hit it nearly
immediately, there is some sort of logical problem here. If something as
simple as AS_PATH prepending in confederations does not work, I have some
big reservations about things that are much more complex than that.

Nortel has some exellent hardware that they have inherited from Bay
Networks. Unfortunately, they still have not written the software to take
any advantage of it, nor they developed it to the level where it can
actually complete with the new offerings from the other vendors.


Thanks,
Alex


> While a central architecture is simple, it has been shown within and
> beyond the industry that it does not scale.
> 
> David
> 
> 
> -----Original Message-----
> From: alex at yuriev.com [mailto:alex at yuriev.com] 
> Sent: Wednesday, April 11, 2001 1:41 PM
> To: nanog at merit.edu
> Subject: RE: gigabit router (was Re: Getting a "portable" /19 or /20)
> 
> 
> 
> > 
> > Vendors have known how to solve this problem for many years.  
> > Failure to do so is a poor implementation and has nothing to do
> > with centralized forwarding being better/worse than distributed
> > forwarding. 
> 
> Yet another person who does not understand the KISS principle. I am
> sure in theory it all works great, though I am seeing way too many
> comments
> similiar to:
> 
> "The connectivity issues have been resolved.  This appears to be the
> same
> CEF related issues we experienced Monday evening, and we have a case
> open
> with Cisco.  As we get more information from Cisco, we will be passing
> it 
> along."
> 
> Alex
> 
> 
> 






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