WAAS Quesrion

[asmith1972]

Hi We have a MPLS network with numerous sites but all our apps run from a central location.

Anyway we'd like to put a WAAS device on 1 of the remote sites to see if it improves the performance of the apps. If we do this dow we just need to get 1 WASS box for the remote site or do we need 2 - 1 at the remote end and 1 at the data centre?

Also anyone know if there is a doc - saying WAAS speeds up Citrix, Exchange etc.. traffic by x amount?

Thanks

Cheers

[joshtseng]

CRC? The only CRC I'm aware of is at the Ethernet layer, and that would be generated by the switch or router local to the destination host. Why would there be a CRC mismatch in this case?

Thanks in advance for your help.

[aamittle]

TCP checksum, not CRC... sorry for the miscue.

[aamittle]

.

[bhedlund]

"Correct addressing" ... LOL! What a joke.

This is the third term I think they have come up with now.

The fact is this, Riverbed changes both the source and destination of the packet. This fundamentally changes the identity and routing behavior of the traffic from the original design and intent of the topology. If looks like a tunnel and acts like a tunnel ... guess what? Its a TUNNEL!

Riverbed's tunnel based architecture might be OK for the smaller networks where things like QoS, network analysis and security dont have alot of importance.

However, in the larger enterprise networks where true transparency and security does matter, Riverbed is not bearing scrutiny very well and Cisco WAAS is winning deal after deal. I see it every day.

[osiristrading123]

Regarding QoS - how does NBAR behave when it sees optimized packets? Does it only do identification at L4, or is there some mechanism to allow L5-7 discovery?

[aamittle]

NBAR policies thru L4 will perform as normal. L5-7 policies would need to be configured on the inside (LAN) interfaces of the router.

[sdavis_199]

I don't understand. Why would the TCP checksum be invalid? Does the WAAS device send invalid TCP checksums?

[Zach Seils]

Siachen,

Just to clarify what was previously posted ...

The TCP sequence number used for the optimized connection is different from that which is used on the client/server original connections. In the event that an optimized packet is received by the client/server, it should be ignored because the TCP sequence number is outside the expected window. So it is not the checksum, but rather the TCP sequence number.

Thanks,

Zach

[Zach Seils]

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Thanks,

Zach