Enterprise QoS Solution Reference Network Design Guide

Chapter 3 WAN Aggregator QoS Design
Slow-Speed (£768 kbps) Leased Lines
Version 3.3
WAN Edge Link-Specific QoS Design
Recommendation: Use MLP LFI and cRTP.
For slow-speed leased lines (as illustrated in Figure 3-7), LFI is required to minimize serialization delay.
MLP, therefore, is the only encapsulation option on slow-speed leased lines because MLP LFI is the only
mechanism available for fragmentation and interleaving on such links. Optionally, cRTP can be enabled
either as part of the MQC policy map
(as shown in Example 3-10) or under the multilink interface (using the ip rtp header-compression
command). Ensure that MLP LFI and cRTP, if enabled, are configured on both ends of the point-to-point
link, as shown in Example 3-14.
Figure 3-7 Slow-Speed Leased Lines
WAN Aggregator
Example 3-10 Slow-Speed (£768 kbps) Leased-Line QoS Design Example
!
policy-map WAN-EDGE
class Voice
priority percent 33 ! Maximum recommended LLQ value
compress header ip rtp ! Enables Class-Based cRTP
class Call Signaling
bandwidth percent 5 ! BW guarantee for Call-Signaling
… ! A 3 to 5 Class Model can be used
!
interface Multilink1
description 768 kbps Leased-Line to RBR-3745-Left
ip address 10.1.112.1 255.255.255.252
service-policy output WAN-EDGE ! Attaches the MQC policy to Mu1
ppp multilink
ppp multilink fragment delay 10 ! Limits serialization delay to 10 ms
ppp multilink interleave ! Enables interleaving of Voice with Data
ppp multilink group 1
!
…
!
interface Serial1/0
bandwidth 786
no ip address
encapsulation ppp
ppp multilink
ppp multilink group 1 ! Includes interface Ser1/0 into Mu1 group
!
Verification commands:
show policy
show interface
show policy interface
show ppp multilink
MLP Link
768 kbps
Branch Router
Enterprise QoS Solution Reference Network Design Guide
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