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Diffserv marked pockets

Dear All,

I was reading through the groups archive looking for information on setting diffserv on cisco routers. I have only one question stayed open:

I have a bunch of VoIP boxes eg sipura, grandstream, audiocodes here to test with. each of them has different style of setting up diffserv values. one needs 43, the other 0xb8, etc etc,

Are all different boxes marking pockets different ways? What I'm missing here?

The question is how can I set up the cco to match up these values? has anyone did it previously?

Any help is greatly appreciated, TIA, Alex

Reply to
Alex Turtois
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For VOIP, the correct DiffServ value is EF (Expedited Forwarding).

The EF DiffServ also contains the ToS Low Delay bit, which is treated by many routers without any configuration. This is called PFIFO (Priority Fist In First Out, or FIFO with Priority).

EF DiffServ decimal: 184 EF DiffServ hexadecimal: 0xb8 EF DiffServ binary: 10111000

EF DSCP decimal: 46 EF DSCP hexadecimal: 0x2e EF DSCP binary: 101110

Remark: The DSCP field is contained within the 6 first bits of the DiffServ byte.

The recommended DSCP value for EF PHB is 101110.

For more information about EF PHB, refer to RFC 2598, An Expedited Forwarding PHB.

Vendors may be configuring the EF value in different way - i.e. in hex which would be 0xb8.

The bottom line is when the VOIP packet are put on the wire the Differv value should be EF.

When acquiring VOIP phones, ensure they are RFC 2598 compliant.

Reply to
Merv

Thanks a LOT, that made my mind clear. Alex

Reply to
Alex Turtois

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