Can someone know 'collisions' in cRTP

[szawdzin]

in IOS 12.2(13)T3 i found one new information in "show ip rtp header-compression" : collisions.

There are no explanation on CCO what's means "collicions" in cRTP

Anybody know how to interpret this??

(on my network its nonzero value aprox. 2% of compressed packets count)

[jbayuka]

I do not see any such field in the command output of a 12.2(13)T version documentation as found here

http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122newft/122tcr/122tip3r/mult/p3ftmlt3.htm#1022461

Would you mind sharing your command output on the forum?

[vinodhjoseph]

I have some extra info. to sharewith. I'm also facing similar issues here.

I have my Routers with IOS Version 12.2(13)T5 at both India and UK . Router at UK is 7206 ( NPE400 ) and Router on India is 7206-VXR and we just enabled cRTP.

See this output:

In-Contd_7206_02>show ip rtp header-compression

RTP/UDP/IP header compression statistics:

Interface Serial1/1:

Rcvd: 1582413 total, 1564458 compressed, 0 errors, 0 status msgs

0 dropped, 0 buffer copies, 0 buffer failures

Sent: 1446690 total, 1428427 compressed, 0 status msgs

29996967 bytes saved, 70233791 bytes sent

1.42 efficiency improvement factor

Connect: 16 rx slots, 16 tx slots,

405940 long searches, 5596 misses 2232 collisions, 0 negative cach

hits

99% hit ratio, five minute miss rate 0 misses/sec, 0 max

In-Contd_7206_02>show ip tcp header-compression

TCP/IP header compression statistics:

Interface Serial1/1:

Rcvd: 2122160 total, 2085996 compressed, 0 errors, 0 status msgs

0 dropped, 0 buffer copies, 0 buffer failures

Sent: 3903889 total, 3188097 compressed, 0 status msgs

112196069 bytes saved, 75577851 bytes sent

2.48 efficiency improvement factor

Connect: 16 rx slots, 16 tx slots,

3626868 long searches, 708119 misses 0 collisions, 0 negative cache

hits

81% hit ratio, five minute miss rate 0 misses/sec, 271 max

Is it something very starnge ? Is this going to affect Voice Quality or CPU Processing ?

Where is the origin for the misses/long search/collisons on that connect side ?

[Chester Rieman]

collisions mean that that the same SSRC is being used by different connections. Try increasing the number of allowed connections ip rtp compression-connections command.

http://www.cisco.com/en/US/products/sw/iosswrel/ps1835/products_configuration_guide_chapter09186a00800b75cb.html#1000953