WCCP mask and weight?

[fernando_garcia]

Hello

We're setting up an scenario with datacenter with three WAEs using WCCP to distribute the load.

The core switches are catalyst 6500 so we're using redirect in. L2 redirection and mask to optimize forwarding of redirected packet.

the problem is that the three WAEs are not equal. Two are 612-2GB and the other is a 7341, so we want to use the weight parameter of the wccp tcp-promiscuous command, but I'm not sure if this parameter works also with the mask mode or only with hash mode. And couldn' t find a definitive answer in the documentation.

It's possible?

Regards, Fernando

[Michael Korenbaum · Accepted solution]

Fernando,

Typically we don't see/ nor recommend using such different devices, especially in the data center.  The 7341 can handle up to 12000 concurrent optimized connections, and the 612-2GB can only handle up 4800 concurrent optimized connections.   So, in the event of a 7341 failure you will lose more than half of the connection capacity you data center can handle.

However, you can use the weight keyword with mask assignment.  I just confirmed in my lab two WAEs connected to a 6500 with the following config:

WAE 14.110.3.19

wccp router-list 1 14.110.3.17

wccp tcp-promiscuous mask src-ip-mask 0xf dst-ip-mask 0x0

wccp tcp-promiscuous router-list-num 1 weight 90 l2-redirect mask-assign

wccp version 2

WAE 14.110.3.20

wccp router-list 1 14.110.3.17

wccp tcp-promiscuous mask src-ip-mask 0xf dst-ip-mask 0x0

wccp tcp-promiscuous router-list-num 1 weight 10 l2-redirect mask-assign

wccp version 2

6500 output:

pdi-6500#sh ip wccp 61 det

WCCP Cache-Engine information:

Web Cache ID:          14.110.3.20

Protocol Version:      2.0

State:                 Usable

Redirection:           L2

Packet Return:         GRE

Packets Redirected:    0

Connect Time:          00:00:45

Assignment:            MASK

Mask  SrcAddr    DstAddr    SrcPort DstPort

----  -------    -------    ------- -------

0000: 0x0000000F 0x00000000 0x0000  0x0000

Value SrcAddr    DstAddr    SrcPort DstPort CE-IP

----- -------    -------    ------- ------- -----

0014: 0x0000000E 0x00000000 0x0000  0x0000  0x0E6E0314 (14.110.3.20)

0015: 0x0000000F 0x00000000 0x0000  0x0000  0x0E6E0314 (14.110.3.20)

Web Cache ID:          14.110.3.19

Protocol Version:      2.0

State:                 Usable

Redirection:           L2

Packet Return:         GRE

Packets Redirected:    68

Connect Time:          00:00:39

Assignment:            MASK

Mask  SrcAddr    DstAddr    SrcPort DstPort

----  -------    -------    ------- -------

0000: 0x0000000F 0x00000000 0x0000  0x0000

Value SrcAddr    DstAddr    SrcPort DstPort CE-IP

----- -------    -------    ------- ------- -----

0000: 0x00000000 0x00000000 0x0000  0x0000  0x0E6E0313 (14.110.3.19)

0001: 0x00000001 0x00000000 0x0000  0x0000  0x0E6E0313 (14.110.3.19)

0002: 0x00000002 0x00000000 0x0000  0x0000  0x0E6E0313 (14.110.3.19)

0003: 0x00000003 0x00000000 0x0000  0x0000  0x0E6E0313 (14.110.3.19)

0004: 0x00000004 0x00000000 0x0000  0x0000  0x0E6E0313 (14.110.3.19)

0005: 0x00000005 0x00000000 0x0000  0x0000  0x0E6E0313 (14.110.3.19)

0006: 0x00000006 0x00000000 0x0000  0x0000  0x0E6E0313 (14.110.3.19)

0007: 0x00000007 0x00000000 0x0000  0x0000  0x0E6E0313 (14.110.3.19)

0008: 0x00000008 0x00000000 0x0000  0x0000  0x0E6E0313 (14.110.3.19)

0009: 0x00000009 0x00000000 0x0000  0x0000  0x0E6E0313 (14.110.3.19)

0010: 0x0000000A 0x00000000 0x0000  0x0000  0x0E6E0313 (14.110.3.19)

0011: 0x0000000B 0x00000000 0x0000  0x0000  0x0E6E0313 (14.110.3.19)

0012: 0x0000000C 0x00000000 0x0000  0x0000  0x0E6E0313 (14.110.3.19)

0013: 0x0000000D 0x00000000 0x0000  0x0000  0x0E6E0313 (14.110.3.19)

So you will see the WAE with weight of 90 took 14 of the 16 available buckets.

Sorry for the confusion on the original update.

Regards,

Mike Korenbaum

Cisco WAAS PDI Help Desk

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

[fernando_garcia]

Hi Mike

Thanks a lot for the information. I'll work with that.

The use os diferent devices is only temporary.

Regards, Fernando

[Michael Korenbaum]

Fernando,

As a follow up, I'd suggest you review the configuration guide section on WCCP weight assignment.

http://www.cisco.com/en/US/docs/app_ntwk_services/waas/waas/v431/configuration/guide/traffic.html#wp1041923

Snippet from the config guide regarding weight:

c. In the Weight field, specify the weight value that is used for load balancing. The weight value ranges from 0 to 10000. If the total of all the weight values of the WAEs in a service group is less than or equal to 100, then the weight value represents a literal percentage of the total load redirected to the device for load-balancing purposes. For example, a WAE with a weight of 10 receives 10 percent of the total load in a service group where the total of all weight values is 50. If a WAE in such a service group fails, the other WAEs still receive the same load percentages as before the failure; they will not receive the load allocated to the failed WAE.

If the total of all the weight values of the WAEs in a service group is between 101 and 10000, then the weight value is treated as a fraction of the total weight of all the active WAEs in the service group. For example, a WAE with a weight of 200 receives 25 percent of the total load in a service group where the total of all the weight values is 800. If a WAE in such a service group fails, the other WAEs will receive the load previously allocated to the failed WAE. The failover handling is different than if the total weights are less than or equal to 100.

By default, weights are not assigned and the traffic load is distributed evenly between the WAEs in a service group.

Regards,

Mike