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SRE-710 as Head-end


Have a question, i'm a bit n00b to WAAS.

We're working on a Try and Buy with cisco for WAAS. We have 3x SRE-710 with WAAS for Medium deployment and Enterprise license, have the central manager, and a WAVE-694 appliance with in-line card. As part of the try-and-buy, my branch sites were configured with the SRE modules and WCCP and the WAVE box is in my datacenter and sits inline between the core and my WAN router. I also got the SSL acceleration to work so I can optimize SSL traffic as well.

WAVE-694 appliance is my "head end" unit.

We're looking to possibly remove most fo the WAAS infrastructure but would like to keep a few pieces for a point-solution for one application...

We have a router in a vendor's datacenter with a private WAN circuit to provide our users access to their SSL-based web application. There

I want to enable WAAS Express on the remote router (after upgrading RAM etc), and use one of the SRE modules in my datacenter router WAN router. I read that a WAAS Express router requires a "Head-end" in a FAQ on Cisco's site.

Can I use SRE-710 as the head-end unit? We want to keep experimenting with the technology but want to minimize costs.


You may want to discuss this strategy with your account team.  It may not work as desired.  To get the full feature set of WAAS express, the clients need to be at the express side and the resource at the core.  You are describing the reverse.

Configuring WAAS Express


WAAS Express compresses upload traffic (with  some limitations) by using the DRE algorithm. WAAS Express decompresses  the download traffic that is compressed using DRE.

With WAAS Express Phase 2, DRE compression is also supported in  the upload direction. You can enable or disable the upload DRE  operations for troubleshooting purposes.

Upload DRE is useful in the download-edit-upload scenario, where a  user in a branch office downloads a file from the data center, modifies  the file, and uploads the modified document back to the data center. If  the modifications are small and localized, the upload of the modified  file can benefit from the unmodified contents stored in the DRE cache.  The compression in the upload direction is performed based on the cache  entries that were added in the download direction.

SSL-Express Accelerator

SSL-Express accelerator operates only on flows  where WAAS Express is configured on an edge device; SSL-Express  accelerator is not applied to a connection if the WAAS Express device  acts as a core device for an SSL session. In addition, WAAS Express  applies SSL-Express acceleration only if the connections originate from  the branch; the connections originating from the data center are not  optimized.

[Though you have a SRE710 at one end.  The SSL servers are at the Waas Express edge.  Client from the core will be traversing the WAN to the edge to the get to the SSL server.  SSL-Express will not be leveraged in this design.]

You can use WAAS-Express with some gains.  TFO will be applied to the flow but that may not scale to what you are envisioning.

Thank You,

Dan Laden

Cisco PDI Data Center

Want to know more about how PDI can assist you?


Hi Daniel,

I'm also trying to setup a WAAS Express deployment for one of our customers. My only concern at the moment is cost especially on the Headend device like 7541, so i was looking at the WAVE 694.

I wanted to know more about the PDI but your youtube video is showing Private, could you give me access to it?

Thanks & Regards




Hi Again,


Don't know whether you fulfill this requirement, but you need to be a Cisco partner to use pdi-helpdesk.

Not sure about the access to the youtube video though.


Best regards



Hi Finn,

Yes i work for Cisco Gold Partner in South Africa.

I was trying to follow the youtube link in Daniel's response.

Thanks & Regards



Ok thanks for setting me straight... What if I have an SRE at both ends? Would that work?

Sent from Cisco Technical Support iPhone App



Technically you can use SRE as a head end for WAAS X or SRE. SRE is as good as a  WAAS appliance from a functionality perspective.

However from the resource perspective SRE is not recommended for head end deployments since it is positioned for branches and has no peering. If you refer to the WAAS Sizing Guidelines you will see that for SRE modules there is no mention of the peer fan-out ratio whereas for the Appliances starting from 594 you will see it mentioned. Peer-Fan out ratio is the maximum number of peer WAAS devices recommended per device. Typically this is needed for Core deplyoments in DCs where traffic from all the branches get into.

Hope this helps.