In fact packets are only queued when there is congestion wheather it is LLQ or a regular shaping queue. When there is no congestion, packest are direclty forwarded to the interface hardware queue, bypassing the entire queuing system.
Again I would say look at the page number 481 in R & S guide (third edition) by wendell odom, It is explained with a diagram. Thanks Suresh On Feb 17, 2008 8:01 PM, Scott Morris <[EMAIL PROTECTED]> wrote: > > As always, it depends on your criteria! Watch the lab for details. But > yes, you have multiple things to think about there other than just straight > policing! > > Scott > ________________________________ > > From: Derek Winchester [mailto:[EMAIL PROTECTED] > Sent: Sunday, February 17, 2008 7:52 PM > To: Victor Cappuccio > Cc: [EMAIL PROTECTED]; [email protected] > > > Subject: Re: [OSL | CCIE_RS] Shape vs Police question > > > > So to clarify, are you stating that the response/answer could be shaping or > LLQ? Well the fact that LLQ only works in time of congestion negates LLQ, so > the answer would be shaping. Is there any other answers. I don't want to be > fuzzy right, i think this discussion has open up the possibility that limit > could mean more than just policing and can include more than just shaping. > > > > On 2/17/08, Victor Cappuccio <[EMAIL PROTECTED]> wrote: > > hmmm right.. > > > > Thanks > > > > > > > > On Feb 18, 2008 1:35 AM, Scott Morris <[EMAIL PROTECTED]> wrote: > > > > > > > > > > > The "priority" keyword only polices during times of congestion. but > yes, that is an added feature as well! > > > > > > > > > > > > > > > > > > > > > Scott Morris, CCIE4 (R&S/ISP-Dial/Security/Service Provider) #4713, > JNCIE-M #153, JNCIS-ER, CISSP, et al. > > > CCSI/JNCI-M/JNCI-ER > > > VP - Technical Training - IPexpert, Inc. > > > IPexpert Sr. Technical Instructor > > > > > > A Cisco Learning Partner - We Accept Learning Credits! > > > > > > [EMAIL PROTECTED] > > > > > > > > > > > > Telephone: +1.810.326.1444 > > > Fax: +1.810.454.0130 > > > http://www.ipexpert.com > > > > > > > > > > > > ________________________________ > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Victor Cappuccio > > > Sent: Sunday, February 17, 2008 6:50 PM > > > To: Derek Winchester > > > Cc: [email protected] > > > Subject: Re: [OSL | CCIE_RS] Shape vs Police question > > > > > > > > > > > > > > > > > > LLQ when the traffic exceed the configured Priority it gets dropped > > > > > > R1#conf ter > > > Enter configuration commands, one per line. End with CNTL/Z. > > > R1(config)#access-list 101 permit ip any any pre 3 > > > R1(config)#class-map TEST > > > R1(config-cmap)#ma access-gr 101 > > > R1(config-cmap)#exit > > > R1(config)#policy-map TEST > > > R1(config-pmap)#class TEST > > > R1(config-pmap-c)#prio 250 > > > R1(config-pmap-c)#exit > > > R1(config-pmap)#int s1/1 > > > R1(config-if)#serv out TEST > > > R1(config-if)#do show policy-map int s1/1 > > > Serial1/1 > > > > > > Service-policy output: TEST > > > > > > Class-map: TEST (match-all) > > > 0 packets, 0 bytes > > > 5 minute offered rate 0 bps, drop rate 0 bps > > > Match: access-group 101 > > > Queueing > > > Strict Priority > > > Output Queue: Conversation 264 > > > Bandwidth 250 (kbps) Burst 6250 (Bytes) > > > (pkts matched/bytes matched) 0/0 > > > (total drops/bytes drops) 0/0 > > > > > > Class-map: class-default (match-any) > > > 1 packets, 84 bytes > > > 5 minute offered rate 0 bps, drop rate 0 bps > > > Match: any > > > R1(config-if)# > > > > > > R1#ping > > > Protocol [ip]: > > > Target IP address: 3.3.3.3 > > > Repeat count [5]: 10 > > > Datagram size [100]: 1000 > > > Timeout in seconds [2]: 0 > > > Extended commands [n]: y > > > Source address or interface: > > > Type of service [0]: 0x60 > > > Set DF bit in IP header? [no]: > > > Validate reply data? [no]: > > > Data pattern [0xABCD]: > > > Loose, Strict, Record, Timestamp, Verbose[none]: > > > Sweep range of sizes [n]: > > > Type escape sequence to abort. > > > Sending 10, 1000-byte ICMP Echos to 3.3.3.3, timeout is 0 seconds: > > > .......... > > > Success rate is 0 percent (0/10) > > > R1#show policy-map int s1/1 > > > Serial1/1 > > > > > > Service-policy output: TEST > > > > > > Class-map: TEST (match-all) > > > 10 packets, 10040 bytes > > > 5 minute offered rate 2000 bps, drop rate 2000 bps > > > Match: access-group 101 > > > Queueing > > > Strict Priority > > > Output Queue: Conversation 264 > > > Bandwidth 250 (kbps) Burst 6250 (Bytes) > > > (pkts matched/bytes matched) 10/10040 > > > (total rops/bytes drops) 4/4016 > > > > > > Class-map: class-default (match-any) > > > 15 packets, 1092 bytes > > > 5 minute offered rate 0 bps, drop rate 0 bps > > > Match: any > > > R1# > > > > > > Thanks > > > > > > -- > > > Victor Cappuccio > > > www.vcappuccio.wordpress.com > > > > > > > > > On Feb 18, 2008 12:44 AM, Derek Winchester > <[EMAIL PROTECTED]> wrote: > > > > > > > In regards to llq I believe that it wont limit but guarantee the > > > > bandwidth so you can spike above the configured amount if available. > > > > > > > > > > > > > > > > > > > > On 2/17/08, Victor Cappuccio <[EMAIL PROTECTED]> wrote: > > > > > > > > > > Hi Derek, > > > > > > > > > > I heard this question before, I would agree on your answer, but what > about > > > > > also using, LLQ within a CBWFQ, in addition of that priority queue > is > > > > > serviced with a strict priority scheduler in which I do not see any > , and in > > > > > the event of congestion, if the priority queue traffic exceeds the > bandwidth > > > > > guarantee, a congestion-aware policer is used to drop the exceeding > traffic. > > > > > > > > > > Just a thought > > > > > Thank > > > > > > > > > > -- > > > > > Victor Cappuccio > > > > > www.vcappuccio.wordpress.com > > > > > > > > > > > > > > > On Feb 18, 2008 12:23 AM, Derek Winchester > <[EMAIL PROTECTED]> > > > > > wrote: > > > > > > Someone asked me a very good question yesterday and I am still > > > > > > confused if I gave him the correct answer. He gave me a scenario > that > > > > > > states that he has to limit all IP Precedence 3 traffic out of an > > > > > > interface to 256k, but he cannot use policing or rate-limiting. My > > > > > > answer was to use shaping. But from my experience, doesn't the > word > > > > > > "limit" negates that as a possible answer? Even though you can use > > > > > > shaping to limit, I was always under the impression when studying > for > > > > > > the CCIE that if they use the word limit that means no shaping. > Can > > > > > > someone help ease my conscience? > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > -- > > > > Derek S. Winchester > > > > www.myprofessorvoip.com > > > > www.winchester1.com > > > > www.derekspeaks.org > > > > > > > > > > > > > > > > > > > > > > > > > > > -- > > Victor Cappuccio > > www.vcappuccio.wordpress.com > > > > -- > Derek S. Winchester > www.myprofessorvoip.com > www.winchester1.com > www.derekspeaks.org
