Junos
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Junos

Understanding CoS

[ Edited ]
‎03-26-2015 11:13 AM

Hello,

 

I have two EX3300-24p switches, connected to one another over SFP+ modules.

 

Switch 'A'

xe-0/1/0 {
    unit 0 {
        family ethernet-switching {
            port-mode trunk;
            vlan {
                members [ data voip-only ];
            }
        }
    }
}

 Switch 'B'

xe-0/1/0 {
    unit 0 {
        family ethernet-switching {
            port-mode trunk;
            vlan {
                members [ data voip-only ];
            }
        }
    }
}

 

Attached to ge-0/0/1 on switch 'A' is a VoIP phone which supports LLDP-MED.  The phone correctly places itself into the "voip-only" VLAN, with the help of the "ethernet-switching-options voip" stanza.

[edit interfaces]
ge-0/0/1 { description "A VoIP Phone is attached here"; unit 0 { family ethernet-switching { port-mode access; } } } [edit ethernet-switching-options voip] interface ge-0/0/1.0 { vlan voip-only; forwarding-class expedited-forwarding; }

 Attached to ge-0/0/2 on switch 'B' is an IP PBX, also residing on the "voip-only" VLAN.

[edit interfaces]
ge-0/0/2 {
    description "PBX Server attached here";
    unit 0 {
        family ethernet-switching {
            port-mode access;
        }
    }
}

[edit vlans]
voip-only {
    vlan-id 99;
    interface {
        ge-0/0/2.0;
    }
    l3-interface vlan.99;
}

 

I am new to this.  It seems to me that the VoIP phone on Switch 'A' will have its packets handled by the "expedited-forwarding" CoS functionality, but that the PBX on Switch 'B' will not enjoy that same prioritization.  Is that correct?  Are "voip-only" packets prioritized over "data" packets on the trunk connection betweent he two switches, or is additional configuration required to acheive that?

 

What is the best way to ensure that "voip-only" packets are identically prioritized on every interface?

 

Thank you.

1 REPLY 1
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Junos

Re: Understanding CoS

‎04-26-2015 06:51 PM

Hpoing to understand this interaction a little better.  If anyone can provide any insight at all, of course, I am grateful.

 

Thanks!

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