Archive for the ‘WAN’ Category

PPP Virtual template and Frame-relay

Posted: August 30, 2006 by sankar in QOS, WAN

To configure a virtual template for MLP LFI on a frame-relay subinterface, you have to remove the DLCI configured under that subinterface first before reapplying it back with the ppp keyword.

int s0/0

no frame-relay interface-dlci 30

 frame-relay interface-dlci 30 ppp virtual-template 1

Apply any LLQ, IP settings, ppp configs under the virtual template interface.

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* Remove ip address of serial subinterface interface

* Remove DLCI of subinterface.

* Its recommended to do this configuration on the remote site first.

int s0/0.9

no ip address

frame-relay interface-dlci 900 ppp virtual-template 1

int virtual-template 1

ip add 10.1.1.1 255.255.255.0

ppp multilink

ppp multilink interleave

ppp multilink fragment-delay 10 — milliseconds.

service-policy output VATS

Frame relay voice adaptive traffic shaping

Posted: August 19, 2006 by cciestudy in QOS, WAN

** You will need to disable frame relay traffic shaping at the main interface level for this to work **

Configure LLQ for voice 

policy-map BR2-HQ
class RTP
priority percent 33
class Sig
bandwidth percent 2
class class-default
fair-queue
Configure Voice activated FRTS:

policy-map VATS  ———–  Line rate is 768kbps, CIR is 384kbps. Use 95 % of CIR for shape average and shape adaptive.
class class-default
shape average 729600 3648 0 
shape adaptive 364800
shape fr-voice-adapt deactivation 50
service-policy BR2-HQ
Configure FRTS class-map and apply VATS policy to the class-map

map-class frame-relay BR2-HQ
frame-relay fragment 480  ——— configures end-to-end FRF.12 fragmentation based on CIR of 384kbps
service-policy output VATS

interface Serial0/0
no ip address
encapsulation frame-relay
no dce-terminal-timing-enable
frame-relay fragmentation voice-adaptive deactivation 50
!
interface Serial0/0.201 point-to-point
ip address 10.201.2.2 255.255.255.0
frame-relay interface-dlci 201
class BR2-HQ

CIR calculation

Posted: July 10, 2006 by sankar in QOS, WAN

WHen calculating cir and mincir for FRTS, use 95 % of the CIR value. If CIR = 256k, it should be used as 256000. Do not multiply 256 with 1024.

Frame-relay fragment

Posted: July 10, 2006 by sankar in Cisco General, QOS, WAN

Frame-relay fragment is typically not needed for link speeds above 768 kbps.

If CIR is 256k and link speed is 480kbps, frame-relay fragment should be based off of PVC CIR ie 256 K.

Qos for WAN

Posted: May 25, 2006 by sankar in QOS, WAN

Fair Queueing

fair-queue <congestive discard threshold>

fair-queue 128 <dynamic queues> <reservable queues>

after these many packets (128) in each queue, rest of packets are tail dropped

CBWFQ

class-map <name>
match access-group <number>
or
match ip dscp or match dscp
match ip precedence or match precedence
or
match input-interface
or
match protocol <protocol>

policy-map <name>
class <class1>
bandwidth <kbps> or
bandwidth percent <percent>

class <class2>
bandwidth <kbps>
queue-limit <number of packets> — defines number of packets that may be queued for this class

*** Upto 64 classes may be defined inside a policy map.
*** The total bandwidth allocated to all classes should add to 75%
*** 25% is used for routing and control traffic

This value can be changed using
ints0/0
max-reserved-bandwidth <value>

Random Early Detection

Enabling WRED instead of tail drop (which is the default)

policy-map <name>
class <class1>
bandwidth <kbps>
randmom-detect
random-detect exponential-weighting-constant <value>

The exp. weighting constant is used to find out the avg. length of queues.
The first random-detect command enables WRED for that class.

Configuring LLQ

class-map match-all VoiceB
match dscp ef
class-map match-all VoiceC
match dscp af31
class-map match-all Data
match access-group 101
!
!
policy-map CBWFQ
class VoiceB
priority percent 45
class Data
bandwidth percent 20
class VoiceC
bandwidth percent 10
class class-default
fair-queue 128
!
interface Serial0/0 .

encapsulation frame-relay

service-policy output CBWFQ — LLQ cannot be applied to sub interfaces

If you have sub interfaces use this template:
class-map match-all VoiceB
match dscp ef
class-map match-all VoiceC
match dscp af31
class-map match-all Data
match access-group 101
class-map match-all VoiceBearer
!
!
policy-map CBWFQ
class VoiceB
priority percent 45
class Data
bandwidth percent 20
class VoiceC
bandwidth percent 10
class class-default
fair-queue 128
map-class frame-relay LLQ
service-policy output CBWFQ

int s0/0
encapsulation frame-relay
frame-relay traffic-shaping
———– always enable shaping before applying map-class to subinterface
!

int s0/0.101
frame-relay interface-dlci 101
class LLQ

map-class frame-relay LLQ
service-policy output CBWFQ
frame-relay cir 120000
frame-relay mincir 60000

LLQ – Calculating Total bandwidth:
===========================

*** The bandwidth percent allocates bandwidth as a percentage of total bandwidth on link.

*** For a frame-relay PVC ,if minCIR is configured, total bandwidth = mincir
*** For a frame-relay PVC , if minCIR is not configured, total bandwidth = cir/2

*** Default CIR of 56000 bps is applied if no map-class is configured or a map-class with no cir/mincir settings r configured.
Ways to apply LLQ on a FR sub interface:
——————————————

a. Apply it on main interface and disable Traffic shaping and fair queue.

class-map match-all VoiceB
match dscp ef
class-map match-all VoiceC
match dscp af31
class-map match-all Data
match access-group 101
class-map match-all VoiceBearer
!
!
policy-map CBWFQ
class VoiceB
priority percent 45
class Data
bandwidth percent 20
class VoiceC
bandwidth percent 10
class class-default
fair-queue 128

int s0/0
no frame-relay traffic-shaping
no fair-queue
service-policy output CBWFQ
max-reserved-bandwidth 75 —- this is default. YOu may change this. This command is not supported with FR subinterfaces.

b. Apply on sub interface (point to point) using a map-class directly on the sub int. Enable TS on main interface.

class-map match-all VoiceB
match dscp ef
class-map match-all VoiceC
match dscp af31
class-map match-all Data
match access-group 101
class-map match-all VoiceBearer
!
!
policy-map CBWFQ
class VoiceB
priority percent 45
class Data
bandwidth percent 20
class VoiceC
bandwidth percent 10
class class-default
fair-queue 128
map-class frame-relay LLQ
service-policy output CBWFQ
frame-relay cir 120000
frame-relay mincir 60000

int s0/0
frame-relay traffic-shaping

int s0/0.1 p
frame-relay map-class LLQ
c. Apply at VC level (say point to point or PMP) using a map-class directly on the VC. Enable TS on main interface.

class-map match-all VoiceB
match dscp ef
class-map match-all VoiceC
match dscp af31
class-map match-all Data
match access-group 101
class-map match-all VoiceBearer
!
!
policy-map CBWFQ
class VoiceB
priority percent 45
class Data
bandwidth percent 20
class VoiceC
bandwidth percent 10
class class-default
fair-queue 128

map-class frame-relay LLQ
service-policy output CBWFQ
frame-relay cir 120000
frame-relay mincir 60000

int s0/0
frame-relay traffic-shaping

int s0/0.1 m
frame-relay interface-dlci 101
class LLQ
frame-relay interface-dlci 102
class LLQ

Configuring FRTS
——————–

CIR = Bc/Tc (set it to 95% of the actual link speed)

If the link speed is a full T1 (1,544,000), then set the CIR to 1466800

map-class frame-relay test
frame-relay cir 64000 — set to actual cir.
no frame-relay adaptive-shaping becn
frame-relay bc 1000 — keep this low so that Tc is low. (tc = 10ms)
frame-relay be 0

int s0/0
frame-relay traffic-shaping
int s0/0.1
frame-relay interface dlci
class test

Traffic shaping parameters for Voice

For data Bc = CIR / 8, tc – 125ms
For Voice Bc = CIR/100 tc – 10ms
map-class frame-relay FRTS_Site3
frame-relay cir 768000
frame-relay bc 7680
frame-relay be 0
frame-relay mincir 768000
frame-relay fragment 1000
frame-relay fair-queue
map-class frame-relay FRTS_Site2
frame-relay cir 256000
frame-relay bc 2560
frame-relay be 0
frame-relay mincir 256000
frame-relay fragment 320
frame-relay fair-queue

FRF 12 fragmentation:
====================

FRF12 fragments all packets above the specified size. Specify a size greater than voice packet).
Voice packets wont be fragmented. Long data packets get fragmented. Voice packets will be interleaved
between fragmented data packets…

Default fragment size – 53 bytes
g711 160 bytes (voice payload)
g729 20 bytes (voice payload)

Total size of IP header (IP/UDP/RTP) – (20/8/12)
Total g711 packet size = 160 + 40 = 200 bytes
Total g729 packet size = 20 + 40 = 60 bytes

Set frame-relay fragment > 200 bytes (say 220 bytes)

map-class frame-relay test
frame-relay fragment <bytes>

RTP header compression for frame interfaces:
——————————————-

int s0/0.1
frame-relay ip rtp header-compression
## all outgoing is compressed

frame-relay ip rtp header-compression passive
## all outgoing is compressed only if incoming is compressed. Dont give passive option on both ends.
frame-relay ip rtp header-compression iphc-format
## enables TCP headre and RTP header compression
ip rtp header-compression ietf-format

Calculating fragment size using serialization delay

56kbps 70
64 kbps 80 bytes
128 160
256 320
512 640
768 960