WAN Acceleration Configuration

[Jkloza_2]

Hello all,

We have purchased WAAS WAE 674 WAN Accelerator's, and I have a question on placement in our network.  I've just recently implemented redundant WAN Lines (DS3's), and now would like to move my WAE674's so that they are accelerating traffic across both WAN lines.

Is this configuration possible with the 2 WAE674's (no inline cards), and WCCP forwarding, and my HQ WAAS controller, or do I have to purchase an additional 2 WAE 674's to accelarate both WAN lines.

Attached is a drawing for what our WAN design network looks like, we are using EIGRP as our routing protocol, and using per destination load sharing, and redistributing our static routes out from our HQ 6509E.

Please let me know if there is more information needed.

Thanks,

Jon

[Bhavin Yadav]

Hi Jon,

Yo don't need multiple WAEs even if you have more than one WAN link (from the WAN link perspective).

You can place wccp redirect statement on each of the WAN interface on router / switch to enable redirection to WAE to optimize the traffic.

One of the white paper that moght be useful for you to look at:

http://www.cisco.com/en/US/prod/collateral/contnetw/ps5680/ps6870/prod_white_paper0900aecd806d976a.html

In your case, you can connect / pair up WAE with 6509E or 3750E (on the other side) to redirect the traffic to WAE. You can also use 3845s to redirect traffic.

But looking at different hardware you have in your topology, you probably want to go thru the white paper mentioned below to verify your WCCP redirection method support. e.g. 3750 supports L2/Mask only.

http://www.cisco.com/en/US/prod/collateral/contnetw/ps5680/ps6870/white_paper_c11-608042.html

Regards.

PS: Please mark this as Answered, if this answers your question.

[Jkloza_2]

Bhavin,

Thanks!  As someone who has only done the bare minimun with WCCP, it looks like the 3845 ISR's support GRE or L2 mode.  What would be the difference between these two modes?  I don't know what i'm running right now, we kind of took the stock cisco configs for WCCP redirection when we initially set these devices up.

Also, I remember my WAN accelerators needed to be on seperate subnets off of my router, is this still the case?  Now that i'm running EIGRP, do I need to advertise the subnets to the AS, my initial instincts say no because I don't see any reason that i'd have to being directly connected to my L3 devices.

Thanks again for all of your help!

Jon

[Bhavin Yadav]

Hi Jon,

Here are the details of GRE and L2 WCCP redirection.

GRE allows datagrams to be encapsulated into IP packets at the WCCP-enabled router and then redirected to a WAE (the transparent proxy server). At this intermediate destination, the datagrams are decapsulated and then handled by the WAAS software. If the request cannot be handled locally, the origin server may be contacted by the associated WAE to complete the request. In doing so, the trip to the origin server appears to the inner datagrams as one hop. The redirected traffic using GRE usually is referred to as GRE tunnel traffic. With GRE, all redirection is handled by the router software.

Layer 2 redirection is accomplished when a WCCP-enabled router or switch takes advantage of internal switching hardware that either partially or fully implements the WCCP traffic interception and redirection functions at Layer 2. This type of redirection is currently supported only with the Catalyst 6500 series switches and Cisco 7200 and 7600 series routers. With Layer 2 redirection, the first redirected traffic packet is handled by the router software. The rest of the traffic is handled by the router hardware. The branch WAE instructs the router or switch to apply a bit mask to certain packet fields, which in turn provides a mask result or index mapped to the branch WAE in the service group in the form of a mask index address table. The redirection process is accelerated in the switching hardware, making Layer 2 redirection more efficient than Layer 3 GRE.

More details here:

http://www.cisco.com/en/US/docs/app_ntwk_services/waas/waas/v441/configuration/guide/traffic.html

Cisco WAAS Software Release 4.0.13 introduces flexibility when using WCCPv2 as the redirection method. It allows configuration of egress method that increases Cisco WAAS deployment alternatives in cases using WCCP iterception. From Cisco WAAS 4.0.13 onward, the WCCP negotiated return is also supported as the egress method. This method allows the Cisco WAE to be deployed on the same subnet as users or servers and provides better support for preservation of the routing path chosen by the network, because the optimized traffic is returned to the redirecting router. The negotiated return egress method also helps ensure compatibility with asymmetric routing, equal-cost multipath (ECMP) load-balancing, and Hot Standby Router Protocol (HSRP) environments. The return traffic egress method is negotiated based on the WCCPv2 configuration on the router and the egress method configuration on the Cisco WAE.

You will find more information here:

http://www-europe.cisco.com/en/US/prod/collateral/contnetw/ps5680/ps6870/prod_white_paper0900aecd806d976a_ps6474_Products_White_Paper.html

Regards.