Question on WCCPv2 - bucket assignment for WCCP2 load balancing

Question

Hello,
I would like to know if any one has tried out running Cisco's WAAS/WAFS/WAE or
Squid proxy as a cache cluster to leverage load balancing support in WCCPv2.
I am trying to understand WCCP based transparent network redirection in a lab setup using squid cache's WCCP and Cisco routers only. When I tried with 2 proxies for load balancing, I see that the router *always* allocates buckets in the reverse order of the specified assignment - its confusing as its not mentioned in Cisco WCCP2 protocol drafts.
In my case, the lead cache with the lowest IP specifies buckets 0-127 to itself and 128-255 to the other; but the router assigns buckets 0-127 to the second cache and 128-255 to lead cache.
I have attached the ethereal trace. Can someone explain what is going wrong here?
The issue was found in the following router versions:
Cisco 3600, IOS 12.3(1a);
Cisco 2600 IOS 12.3(9a);
Cisco 2800 IOS 12.4(3d)
Squid proxy:
2.5
WCCP status output - all the routers above show the same behavior.
From the trace, 192,168.8.231 specifies bucket distribution as its the
lead cache with a lower IP than 192.168.41.232.
router#sh ip wccp 99 detail
WCCP Cache-Engine information:
Web Cache ID: 192.168.41.232
Protocol Version: 2.0
State: Usable
Initial Hash Info: 00000000000000000000000000000000
00000000000000000000000000000000
Assigned Hash Info: 00000000000000000000000000000000 FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
Hash Allotment: 128 (50.00%)
Packets Redirected: 0
Connect Time: 00:23:06
Bypassed Packets
Process: 0
Fast: 0
CEF: 0
Web Cache ID: 192.168.8.231
Protocol Version: 2.0
State: Usable
Initial Hash Info: 00000000000000000000000000000000
00000000000000000000000000000000
Assigned Hash Info: FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
00000000000000000000000000000000
Hash Allotment: 128 (50.00%)
Packets Redirected: 0
Connect Time: 00:23:05
Bypassed Packets
Process: 0
Fast: 0
CEF: 0
Thanks in advance.

Answer 1

I'm not an expert of the details of wccp, but looks like the squid is not setting the bucket info correctly.
From the draft [below], the first bit is the the A flag - for alternative hashing.
And the alternative hashing is determined by another flag in the service info.
So, why is Squid setting this bit ?
I feel like they forgot to shift the index by 1 bit to the left.
Bucket 0-255
Contents of the Redirection Hash Table. The content of each bucket is a
web-cache index value in the range 0-31. If set the A flag indicates
that alternative hashing should be used for this web-cache. The value
0xFF indicates no web-cache has been assigned to the bucket.
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
| Index |A|
+-+-+-+-+-+-+-+-+
I'm double checking with a developpers for our cache, but I feel like this is the explanation.
More info to come if I'm wrong.
Gilles.