Hi Peter, Thanks for the detailed reply. I forgot to include the router platforms we are using for this.
[GROUP1] --> [ POP1] <--> [POP2] --> [HOSTED SERVICES + INTERNET] POP1 = Cisco 7204VXR (NPE-G1) GigE Interface running 12.2(31)SB13 POP2 = Cisco 7606 with 4-subslot SPA Interface (7600-SIP-400) running 12.2(33)SRB3 1/ "If you have a 200mbps connection going out from GigabitEthernet-link your prioritising won't take effect, since buffers will never saturate." So if we were to prioritize something like Voice, we would need to implement some Heirarchical QoS solution on the Cisco 7606??? 2/ I understand your arguments exactly about not prioritizing ICMP traffic, but I was told to look into this. I guess based on 1/ above, some form of Heirarchical QoS solution is needed for this also. Cheers. Andy -----Original Message----- From: Peter Rathlev [mailto:[email protected]] Sent: Wednesday, 25 March 2009 12:38 PM To: Andy Saykao Cc: [email protected] Subject: Re: [c-nsp] Question about CBWFQ and PING times Hi Andy, On Wed, 2009-03-25 at 11:15 +1100, Andy Saykao wrote: > 1/ We have a 200mb link between two POPS that is being congested in > the evening. Congestion is happening on the outbound direction from > POP2 to POP1, so from a user's perspective in GROUP1 it would be > impacting their download. ... > interface GigabitEthernet4/0/2 > service-policy output POP2-POP1-QOS-POLICY > > I can see matches for this when doing a show policy-map interface. Is > it as simple as this to ensure that users in GROUP1 will be assured of > bandwidth to access our hosted services? If you have a 200mbps connection going out from GigabitEthernet-link your prioritising won't take effect, since buffers will never saturate. Heirarchical QoS (as discussed thoroughly many times recently on this list) with a parent shaper could solve this, but it is uncertain if your platform can do this. What hardware and IOS version are you using? Another possibility would be to police some of the traffic that causes the congestion, which even the least feature rich switches with L3 features can do. If you have some SRR-device (Catalyst 3560, 3750, some 6500 modules) you could do some crude shaping, but the number of queues available often makes this an interesting task and traffic limited this way could be an unpleasant experience for the users. > 2/ If I wanted to prioritze ping times between POP1 to POP2, how would > this be done? On a side note: Giving priority to ICMP Echo is in my eyes a bad strategy. This is almost by definition not important business traffic, so the main reason to give it higher priority would be to avoid problematic questions from incompetent users who only know how to measure latency and loss this way. It will not give them a better experience in using the network connection itself and might instead hide certain symptoms that could be helpful in troubleshooting one day. Regards, Peter ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email ______________________________________________________________________ This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. Please notify the sender immediately by email if you have received this email by mistake and delete this email from your system. Please note that any views or opinions presented in this email are solely those of the author and do not necessarily represent those of the organisation. Finally, the recipient should check this email and any attachments for the presence of viruses. The organisation accepts no liability for any damage caused by any virus transmitted by this email. _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
