Maybe priority queue is a misuse of the term. But my understanding is that in IOS, there is a special queue for packets tagged internally as pak_priority (all routing protocols except bgp). This shields them from going to class-default and effectively gives them access to the 100% - max reservable bandwidth. Therefore they get priority to the tx- ring(but not necessarily cassified in the priority queue I suppose?). I'm not sure how different the ASA is in this regard.
On May 14, 2010, at 11:41 AM, Brandon Carroll <[email protected]> wrote: > I'd have to revisit this, because it's been some time since I've > done anything with it, but I recall something from the old QOS class > about the max-reservable bandwidth is defaulted to 75% of the link > bandwidth so that routing protocols and other traffic can have a > little breathing room. Like I said, I'll have to revisit this, but > I think this may be the case. I don't think routing protocol > traffic actually uses the "priority" queue on Cisco routers, unless > you classify the traffic and put it there. > > Sorry if I'm off base here, just thinking out loud. > > > > Regards, > > Brandon Carroll - CCIE #23837 > Senior Technical Instructor - IPexpert > Mailto: [email protected] > Telephone: +1.810.326.1444 > Live Assistance, Please visit: www.ipexpert.com/chat > eFax: +1.810.454.0130 > > IPexpert is a premier provider of Self-Study Workbooks, Video on > Demand, Audio Tools, Online Hardware Rental and Classroom Training > for the Cisco CCIE (R&S, Voice, Security & Service Provider) > certification(s) with training locations throughout the United > States, Europe, South Asia and Australia. Be sure to visit our > online communities at www.ipexpert.com/communities and our public > website at www.ipexpert.com > > Platinum Solutions Group (PSG) provides high-end consulting services > with a primary emphasis on Cisco's Data Center Solutions, Service > Provider Solutions, Unified Communications and Security-enabled > infrastructures. Be sure to visit www.platinumsolutionsgroup.com. > > > > On May 14, 2010, at 5:37 PM, Paul Stewart wrote: > >> I think this is not just an ASA thing. It seems that routing protocol >> traffic is always handled by the priority queue on a router as well. >> >> >> >> On May 14, 2010, at 3:06 AM, Anantha Subramanian Natarajan >> <[email protected] >>> wrote: >> >>> Hi All, >>> >>> Was reading through Chapter 11(QOS) on the Cisco ASA:All-in-One >>> Firewall,IPS,Anti-X, and VPN Adaptive security appliance" book and >>> inferring >>> the below sentence from that >>> >>> "Certain critical keep-alive packets such as EIGRP hello packets are >>> never >>> dropped even if they are not prioritized in the shaped traffic" >>> >>> Have a question on that, >>> >>> 1) Is all protocols hello packets treated that way in Cisco ASA and >>> if so, >>> how Cisco ASA keeps track of that to have this exception. >>> >>> Thanks for the help >>> >>> Regards >>> Anantha Subramanian Natarajan >>> >> _______________________________________________ >> For more information regarding industry leading CCIE Lab training, >> please visit www.ipexpert.com > _______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com
