How to prevent IGP packets drop between 7206 & ASA5550?

Unanswered Question
Sep 30th, 2009

We plan on running OSPF between a pair of 7206's and a pair of ASA5550's.

I tested it in the lab, and everything worked to my expectation.

One thing I didn't have in the lab though is a load generator.

How do I ensure the OSPF (or EIGRP if we decide to change it) packets aren't dropped due to excessive traffic?

If I remember correctly, routers & switches prioritize IGP packets internally (IPP==6?) in its control plane.

What about ASA's?

Do they have the same internal QoS feature?

I have this problem too.
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Giuseppe Larosa Thu, 10/01/2009 - 07:15

Hello Kevin,

first of all not all router platforms have an hidden system queue for routing protocols messages.

So this is a question that should be addressed.

About ASA it has some QoS capabilities, for ASA 8.1 version here is the config chapter:

It supports some parts of modular QoS with policy maps and forms of queueing.

the best choice is to create a class-map for routing traffic to be sure to have enough resources to send out hellos during high peak times.

I would do so also on the C7200 side.

I can say that C7500 and GSR hasn't the hidden system queue. I'm not sure about the C7200.

the amount of BW to specify for the class should be enough to exchange hellos and in the case of OSPF to allow LSA refresh (that happens every 30 minutes so its BW usage is low).

Routers like C3640 and ISR (2800, 3800) have the hidden system queue that uses by default 25% of link speed.

Hope to help



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