Layer II Circuit

[aali]

I have a 300MB TimeWarner  Ethernet circuit between my Home Office and Colo and wanted to know if I could assign bandwidth/QOS based on VLANS.  For Example, VLAN 200 will be dedicated to Storage traffic, VLAN300 will be dedicated to Database traffic and so on.  I don't want one type of traffic dominated the whole circuit and wante to assign specifc bandwdith to each type of traffic.

At home office, I have HP 5400zl switch, and at the colo we purchased an HP A-5830 switch.

Please advise if the above possible or alternate solution.

Regards,

[paulgear]

Hi aali,

Whether you can do this is dependent upon whether your Time Warner circuit passes VLAN tags through without interference.  This is normally called Q-in-Q.  You should ask them whether that's something the circuit can do, but the easiest method is just to test it.  Tag a test VLAN on both ends of the link, assign some IP addresses, and see if you can ping.

If your link doesn't provide Q-in-Q, your simplest option is probably to use a routed connection and configure different subnets on each end of the link.

[aali]

Hi Paul,

Thank you for your response.  Yes, the TW will be able to pass VLAN tagging between the sites, but I will also test it.

Now, what be the easiest method to assign bandwidth per VLAN as I stated in my original thread.

Regards,

[paulgear]

Hi aali,

I'll leave the bandwidth capping features to those more qualified than me. If i remember correctly, 5400s don't have that feature, so you might have to do it only on the 5820 end. But it's been a while since i've touched 5400s, so don't take my word for it.

[Vince_Whirlwind]

I still play with 5400s, but I haven't played with "Guaranteed Minimum Bandwidth", which is probably the feature you want.

FIrst, check how many queues you have configured in QoS ("show qos queue-config"). Hopefully you haven't fiddled with this and it is set to its default correspondences.

Then, you assign a bandwidth % for each queue on your outbound "edge" port, eg

int a1-a5 bandwidth-min output 2 3 30 10 10 10 15 20

or

int a1-a5 bandwidth-min output 2 3 30 10 10 10 15 strict

(Queues in order from 1 to 8. "strict" means 8 gets everything it needs. Otherwise if set to "20", 8 gets 20%, plus it gets to use whatever it needs from whatever is unused in all the other queues. Then 7 gets its chance, etc... If your %s don't all add up to 100, then whatever is left over is just unused and available for use by any oversubscribed queues, highest-priority queue getting first choice).

The traffic is assigned a queue according to the 802.1p frame tags.

(HP seem to love using 6 for voice, but normally 802.1p says 5 should be used for voice, I think they've confused TOS 5 with queue 6, or I just haven't understood them properly).

Just looking in the manual, they seem to explain this correctly:

Table 20 Per-port outbound priority queues
802.1p Priority settings in tagged VLAN packets1 Outbound priority queue for a given port
1 (low)                                                                                      1
2 (low)                                                                                      2
0 (normal)                                                                               3
3 (normal)                                                                               4
4 (medium)                                                                             5
5 (medium)                                                                             6
6 (high)                                                                                     7
7 (high)                                                                                     8
 

This is correct, because you shouldn't be using TOS 6 (which is 110) or 7 (111).

But elsewhere, I swear I see them trying to get you to use TOS 6 for voice instead of 5 (correct value of 101).

Mind you, all that can be moot anyway if your upstream provider haven't got their network configured properly: I have a WAN link where a TOS of 4 is prioritised (good, normally used for video), 0 is given default priority, but a TOS of 5 experiences 50% packet loss. And apparently this large, multinational telecom company doesn't understand what they are doing wrong when I tried explaining it to them. Twice. Their guys in suits didn't believe me that they would be doing this, and their guys in jeans didn't see the problem.

[aali]

Thank you Paul and Vince.