Hi Mark, I was cross checking my archives for the QOS to config in IOS. In your example below, for the scenario: Scenario >> Voice Bandwidth( Layer 2 Overhead), NO cRTP compression, ADD use MLPPP over Frame Relay, (No FRF.12 - not compatible with MLPPP anyhow), sampling rate - 20ms: you count 8B for F/R. Shouldn't that be 4B as you mention in a previous scenario, as there's no FRF.12 of course in that case? Kind regards, Juan
_____ From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Mark Snow Sent: Friday, February 15, 2008 4:46 PM To: ccievoice1 Cc: CCIE Maillist; [EMAIL PROTECTED] Subject: Re: [OSL | CCIE_Voice] QoS question Hey ccievoice1, This was covered by a post in a bit of excess not a month ago (Jan 24 I believe) - but nevertheless I posted all of the scenarios and calculations from that email below for your reference: Scenario >> Voice Bandwidth( Layer 2 Overhead), [compress header ip rtp] sampling rate - 20ms: 20 bytes <-- G.729 media payload> 2 bytes <-- L3/L4 Header Compressed with cRTP (Normal sizes WITHOUT compression are 20 bytes for IP, 8 bytes for UDP, 12 bytes for RTP: for a total of 40 bytes for the L3/L4 Header)> +4 bytes <-- frame relay header ------------- = 26 bytes *8 bits per byte <-- convert to kilobits> ------------- = 208 bits *50 <-- based on 50 pps> ------------- 10,400 bits per second or 10.4kbps per G729 call (round up to 11Kbps for QoS -- Always want to have slightly more bandwidth - rather than less bandwidth reserved!) ---------------------------------------------------------------------------- ---------------------------------------------------------------------------- ---------------------------------------------------------------------------- ------------------------- Scenario >> Voice Bandwidth( Layer 2 Overhead), NO cRTP compression, sampling rate - 20ms: 20 bytes <-- G.729 media payload> 40 bytes <-- L3/L4 Header Non-Compressed (20 bytes for IP, 8 bytes for UDP, 12 bytes for RTP: for a total of 40 bytes for the L3/L4 Header)> +4 bytes <-- frame relay header ------------- = 64 bytes *8 bits per byte <-- convert to kilobits> ------------- = 512 bits *50 <-- based on 50 pps> ------------- 25,600 bits per second or 25.6kbps per G729 call (round up to 26Kbps for QoS) ---------------------------------------------------------------------------- ---------------------------------------------------------------------------- ---------------------------------------------------------------------------- ------------------------- Scenario >> Voice Bandwidth( Layer 2 Overhead), NO cRTP compression, ADD Frame Relay Fragmentation (FRF.12), sampling rate - 20ms: 20 bytes <-- G.729 media payload> 40 bytes <-- L3/L4 Header Non-Compressed (20 bytes for IP, 8 bytes for UDP, 12 bytes for RTP: for a total of 40 bytes for the L3/L4 Header)> +8 bytes <-- frame relay header with FRF.12 compression ------------- = 68 bytes *8 bits per byte <-- convert to kilobits> ------------- = 544 bits *50 <-- based on 50 pps> ------------- 27,200 bits per second or 27.2kbps per G729 call (round up to 28Kbps for QoS) ---------------------------------------------------------------------------- ---------------------------------------------------------------------------- ---------------------------------------------------------------------------- ------------------------- Scenario >> Voice Bandwidth( Layer 2 Overhead), NO cRTP compression, ADD use MLPPP over Frame Relay, (No FRF.12 - not compatible with MLPPP anyhow), sampling rate - 20ms: 20 bytes <-- G.729 media payload> 40 bytes <-- L3/L4 Header Non-Compressed (20 bytes for IP, 8 bytes for UDP, 12 bytes for RTP: for a total of 40 bytes for the L3/L4 Header)> 13 bytes <-- MLPPP header +8 bytes <-- frame relay header ------------- = 77 bytes *8 bits per byte <-- convert to kilobits> ------------- = 616 bits *50 <-- based on 50 pps> ------------- 30,800 bits per second or 30.8kbps per G729 call (round up to 31Kbps for QoS) Hope that helps some, Mark Snow CCIE #14073 (Voice, Security) CCSI #31583 Senior Technical Instructor - IPexpert, Inc. A Cisco Learning Partner - We Accept Learning Credits! Telephone: +1.810.326.1444 Fax: +1.309.413.4097 Mailto: [EMAIL PROTECTED] IPexpert - The Global Leader in Self-Study, Classroom-Based, Video On Demand and Audio Certification Training Tools for the Cisco CCIE R&S Lab, CCIE Security Lab, CCIE Service Provider Lab , CCIE Voice Lab and CCIE Storage Lab Certifications. On Feb 15, 2008, at 9:58 AM, ccievoice1 wrote: So, a default g729 call is: (20bytes payload + 40bytes header * 8bits) * 50pps = 2400 or 24K So, if cRTP is used for a default g729 call, what would be the calculation? Thanks. On Fri, Feb 15, 2008 at 3:56 AM, Vik Malhi <[EMAIL PROTECTED]> wrote: You can look at a table on page 33 of the QOS SRND for this information. Vik Malhi CCIE Voice Instructor / Developer - IPexpert, Inc. CCIE Voice #13890 CCSI #31584 URL: http://www.IPexpert.com <http://www.ipexpert.com/> Toll Free: +1.866.225.8064 International: +1.810.326.1444 _____ From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of jason sung Sent: Thursday, February 14, 2008 9:47 AM To: boonchin .ng Cc: CCIE Maillist Subject: Re: [OSL | CCIE_Voice] QoS question G729 on frame-relay with FR.12 is not 24K it is 28K so your 5 g729 calls will be 5 x 28 = 140 On Thu, Feb 14, 2008 at 11:36 AM, boonchin .ng <[EMAIL PROTECTED]> wrote: Hi Jason, Thanks for the explanation. So, I would like to understand another scenario. Similarly, I have a 384K frame-relay WAN link, so I have: ! map-class frame-relay FRTS-384 frame-relay cir 364800 frame-relay bc 3648 frame-ralay be 0 frame-relay mincir 364800 frame-relay fragment 480 ! Now, for LLQ I want to configure to only prioritized 5 g729 calls: ! policy-map LLQ class media priority x class control bandwidth 16 class class-default fair-queue ! So, the x value is 5 g729 calls. How can I calculate the x value? Based on CCM bandwidth for a g729? x = 5 x 24 Please kindly advice. Thanks. ---------- Forwarded message ---------- From: jason sung <[EMAIL PROTECTED]> Date: Thu, Feb 14, 2008 at 11:26 PM Subject: Re: [OSL | CCIE_Voice] QoS question To: "boonchin .ng" <[EMAIL PROTECTED]> Cc: CCIE Maillist <ccie_voice@onlinestudylist.com> When you have minCIR configured the LLQ picks 33% of that. If you do not have minCIR configured than the CIR divided by two is used in the calculation. In your example, since you have mincir configured. Priority bandwidth will be 364800 * .33 = about 120K LLQ will allow you to configure 75% of the total bandwidth. if you want to alter this, use the command max-reserved bandwidth xxx -Jason On Thu, Feb 14, 2008 at 5:45 AM, boonchin .ng <[EMAIL PROTECTED]> wrote: Hi, I have a 384K frame-relay link. Hence, I have: ! map-class frame-relay FRTS-384 frame-relay cir 364800 frame-relay bc 3648 frame-ralay be 0 frame-relay mincir 364800 frame-relay fragment 480 ! Now, I want to do LLQ on voice, so: ! policy-map LLQ class media priority percent 33 class control bandwidth percent 5 class class-default fair-queue ! Question: In the policy-map LLQ, I have "bandwidth percent 5". So can I assume that is 5% of the CIR value? If I want to use "priority x" and "bandwidth y" without using the percent command, how I can calculate the bandwidth value for class media and class control? Thanks.
