WCCP with CWAAS WAE

[mnolden]

Dear Community,

By using WCCP Layer 2 forwarding on C6500, C3750 or ASR 1000 series routers to redirect intercepted traffic to the WAAS WAE the Cisco best practive recommends to use MASK ASSIGMENT for load balancing on such switches and ASR routers.

With WAAS versin 4.2.1 and up the default MASK ASSIGMENT is "wccp tcp-promiscuous mask src-ip-mask 0xF00 dst-ip-mask 0x0".

With a typical data center WCCP interception configuration (ingress interception with service 61 on the WAN, ingress interception with service 62 on the LAN), this mask load balances /24 branch subnets (it extracts the last 4 bits of /24 subnets). Connections from one branch subnet will be pinned to one data center WAE.

Question:

How should look like the "src-ip.mask" hex value if I would like to balance per host address instead of a Class C subnet?

A per host /32 load balacing is required on large client-sites where each client ip@ has to be balanced over the WAEs.

I am working on a project and missing the information how I can't find the "src-ip.mask" hex value information for a per host /32 load balancing on a site where only clients are located.

Thanks for your comments and replys

[Michael Korenbaum]

Hi,

I suggest you review the WCCP Mask Calculator on the mycommunity site here, which should answer your question.

https://www.myciscocommunity.com/docs/DOC-9521

Regards,

Mike Korenbaum

Cisco WAAS PDI Help Desk

http://www.cisco.com/go/pdihelpdesk

[mnolden]

Hi Mike,

thank you fro the great tip. That's exactly what I am searching for.

Unfortunately my excel version 2003 converts the file and open it in read-only with some errors. So it is not working correctly.

Is there a chance to get this sheet in excel version 2003 or could you provide me

a) the src-ip-mask of a host address /32

b) the src-ip-mask of a subnet /24

Would be great!

Thank you

[Michael Korenbaum · Accepted solution]

Unfortunately, I did not build the spread sheet so I wouldn't know/ if it's possible to convert to 2003.  I did see on that page that Excel 2007 is mentioned as a requirement for it to work properly.

However, if you want a mask that will match on the 4th octet of your IP scheme use 0x000F (which simplifies to 0xF).  This will create 16 buckets just like the default mask in 4.2.1 (0xF00) but instead will match on the last 4 bits of the 4th octet of your IP.  Where the default mask matches on the last 4 bits of the 3rd octect.

Hope this helps,

Mike