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New Member

Unexpected TOS precedence

I have a customer who is trying to setup various Class of Services by tagging packets with specific TOS bit patterns. Three CoS precedences are defined: flash, immediate, and routine. Although packets are being marked, the marked TOS fields do not appear to make any kind of sense. A sniffer capture shows the following:

flash ==> TOS 0xC0 ?? (expected 0x60)

immediate ==> TOS 0x08 ?? (expected 0x20)

routine ==> TOS 0x00 (OK)

Here is a snippet of the configuration. Any thoughts?


version 12.1


boot system flash c2600-i-mz.121-14.bin

interface Serial0/0.2 point-to-point


ip policy route-map IPFR


access-list 5 permit

access-list 5 permit

access-list 5 permit

access-list 5 deny any

access-list 6 permit

access-list 6 deny any

access-list 10 permit

access-list 10 deny any log

access-list 150 permit tcp any eq telnet any

access-list 151 permit tcp any range ftp-data ftp any

access-list 152 permit tcp any eq www any

route-map IPFR permit 10

match ip address 150

set ip precedence flash


route-map IPFR permit 20

match ip address 151

set ip precedence immediate


route-map IPFR permit 30

match ip address 152

set ip precedence routine


Re: Unexpected TOS precedence

Since there has been no response to your post, it appears to be either too complex or too rare an issue for other forum members to assist you. If you don't get a suitable response to your post, you may wish to review our resources at the online Technical Assistance Center ( or speak with a TAC engineer. You can open a TAC case online at

If anyone else in the forum has some advice, please reply to this thread.

Thank you for posting.

New Member

Re: Unexpected TOS precedence


the config you presented is only to mark certain pakets with a certain ip-prec value.

if this traffic enters a providers cloud, he can set different actions on the diferent prec-values.

For example queueing, drop, ....

This means here you only mark pakets - in the ip-cloud you can react on this values !

Hope this helps -

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