Subject: Re: How Many Routing Tables

From: Bob Welsh <[email-masked]>
Date: Thu, 23 Mar 2000 13:48:00 -0500

We use one routing table, but multiple forwarding tables, depending on TOS. 

	Bob

 At 11:37 AM 3/23/2000 -0600, David Wang wrote:
>Dear Friends,
>
>This may be a silly question but I never found a clear answer form a book or
>a standard. 
>
>A router is running BGP4, OSPF and RIP at the same time. How many routing
>tables(or forwarding tables) this router has? I think there should be only
>one table produced by all the protocols and used by the router to route
>every packet through the router, but I am not sure. Can somebody help get an
>answer ?
>
>Thank you very much
>David
>
>

---

From: Christian Huitema <[email-masked]>
Date: Tue, 28 Mar 2000 09:02:43 -0800

> Just as a follow-up question: Can somebody tell me how many 
> route entries there
> are in edge and core routers nowadays?

Route entries = local routes + BGP acquired routes. For the latter, the
current value is about 78,000, according to the Telstra Internet BGP table
maintained by Geoff Houston at http://www.telstra.net/ops/bgptable.html.

---

From: [email-masked]
Date: Tue, 28 Mar 2000 20:13:56 +0200

Core routers normally have the full routing table. A router in the access
layer should only have 2 paths to the distribution layer. It depends what
you're doing. We try to aggregate routes at the distribution layer.
eg. when you're dialing into an ISP, you want one path to the core and be
able to reach everything from there (internet, server,...)
The size of a routing table depends on how big you're network is. For a NAP
or a core router running BGP, you'll find about 59'000 network entries and
120'000 paths (internet routing table).

Damjan

Nguyen Tuong Long Le <[email-masked]> on 28.03.2000 11:05:28

To:   [email-masked]
cc:
Subject:  Re: How Many Routing Tables

Just as a follow-up question: Can somebody tell me how many route entries
there
are in edge and core routers nowadays?

Thanks,
-- long

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