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New Member

WRED om MPLS links

Hi

On MPLS based on 7500 routers, want to configure WRED on MPLS trunks. In each class I should configure the random-detect command, that can be based on IP Precedence or DSCP. My question is if the random detect shouldn´t be based on EXP bit value, like matches on class maps for MPLS links are based on EXP instead of Ip Prec or DSCP, because on DSCP links we see only the label. So, to configure WRED on MPLS trunks, does it look inside each IP packet, and it is it based on IP Prec or DSPC, or is there any way to configure WRED based on EXP value? What is the recomended configuration? Also, if possible, are there default values with lower-drop probabilities for higher priority classes?

  • MPLS
4 REPLIES
Bronze

Re: WRED om MPLS links

New Member

Re: WRED om MPLS links

jrechtand,

have you found the answer to this problem? Im having the same problem too.

New Member

Re: WRED om MPLS links

Dear all,

I've read from QoS for IP/MPLS by Santiago Alvarez. It says that

"Notice that the WRED implementation will use the MPLS EXP markings for MPLS packets when you configure WRED to use IP precedence or DSCP as the weighting field. Table 3-26 summarizes the weighting fields that can control the operation of WRED."

Is this correct? so the command "random-detect dscp-based" will actually use MPLS EXP for deciding the drop preference?

New Member

Re: WRED om MPLS links

You can use IPPrec to match exp, below configuration i have tested and its working on the MPLS network.

Class COS2

bandwidth remaining percent 53

random-detect precedence-based

random-detect precedence 3 10366 packets 16586 packets 1

random-detect precedence 4 12440 packets 18659 packets 1

Class COS3

bandwidth remaining percent 27

random-detect precedence-based

random-detect precedence 1 8293 packets 14513 packets 1

random-detect precedence 2 10366 packets 16586 packets 1

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