Legacy Frame-Relay Traffic Shaping

This is the most well-known FRTS method, which has been available for quite a while on Cisco routers. It is now being outdated by MQC configurations.
The key characteristic is that all settings are configured under map-class command mode, and later are applied to a particular set PVCs. The
same configuration concept was used for legacy ATM configuration mode (map-class atm).

Legacy FRTS has the following characteristics:

- Enabled with frame-relay traffic-shaping command at physical interface level
- Incompatible with GTS or MQC commands at subinterfaces or physical interface levels
- With FRTS you can enforce bitrate per-VC (VC-granular, unlike GTS), by applying a map-class to PVC
- When no map-class is explicitly applied to PVC, it's CIR and Tc are set to 56K/125ms by default
- Shaping parameters are configured under map-class frame-relay configuration submode
- Allows to configure fancy-queueing (WFQ/PQ/CQ) or simple FIFO per-VC
- No option to configure fancy-queueing at interface level: interface queue is forced to FIFO (if no FRF.12 is configured)
- Allows for adaptive shaping (throttling down to minCIR) on BECN reception (just as GTS) and option to reflect incoming FECNs as BECNs
- Option to enable adaptive shaping which responds to interface congestion (non-empty interface queue)

Example: Shape PVC to 384Kbps with minimal Tc (10ms) and WFQ as interface queue

map-class frame-relay SHAPE_384K

 frame-relay cir 384000

 frame-relay bc 3840

 frame-relay be 0

 !

 ! Adaptive shaping: respond to BECNs and interface congestion

 !

 frame-relay adaptive-shaping becn

 frame-relay adaptive-shaping interface-congestion

 !

 ! Per-VC fancy-queueing

 !

 frame-relay fair-queue

!

interface Serial 0/0/0:0

 frame-relay traffic-shaping

!

interface Serial 0/0/0:0.1

 ip address 177.0.112.1 255.255.255.0

 frame-relay interface-dlci 112

  class SHAPE_384K

Verification: Check FRTS settings for the configured PVC

Rack1R1#show frame-relay pvc 112
PVC Statistics for interface Serial0/0/0:0 (Frame Relay DTE)
DLCI = 112, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE = Serial0/0/0:0
  cir 384000    bc 3840      be 0         byte limit 480    interval 10   <------ Shaping parameters

  mincir 192000    byte increment 480   Adaptive Shaping BECN and IF_CONG <---- Adaptive Shaping enabled

  pkts 0         bytes 0         pkts delayed 0         bytes delayed 0

  shaping inactive

  traffic shaping drops 0

  Queueing strategy: weighted fair  <---- WFQ is the per-VC queue

  Current fair queue configuration:

   Discard     Dynamic      Reserved

   threshold   queue count  queue count

    64          16           0

  Output queue size 0/max total 600/drops 0

The other PVC, with no class configured, has CIR set to 56Kbps and uses FIFO as per-VC queue:

Rack1R1#show frame-relay pvc 113
PVC Statistics for interface Serial0/0/0:0 (Frame Relay DTE)
DLCI = 113, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE = Serial0/0/0:0.2
  cir 56000     bc 7000      be 0         byte limit 875    interval 125 <---- CIR=56K

  mincir 28000     byte increment 875   Adaptive Shaping none

  pkts 74        bytes 5157      pkts delayed 0         bytes delayed 0

  shaping inactive

  traffic shaping drops 0

  Queueing strategy: fifo <------------------ FIFO

  Output queue 0/40, 0 drop, 0 dequeued

Check the physical interface queue:

Rack1R1#show interfaces serial 0/0/0:0 | inc Queue

  Queueing strategy: fifo

- Interface queue could be changed to PIPQ (PVCs are assigned to 4 pririty groups, with PQ being physical interface queue)
- PIPQ stands for PVC Interface Priority queueing

Example: Map PVC 112 traffic to high interface queue, and PVC 113 to low interface queue, with WFQ being per-VC queueing

!

! Shape to 384K an assign to high interface level queue

!

map-class frame-relay SHAPE_384K_HIGH

 frame-relay cir 384000

 frame-relay bc 3840

 frame-relay be 0

 !

 ! Per-VC fancy-queueing

 !

 frame-relay fair-queue

 frame-relay interface-queue priority high
!

! Shape to 256k an assign to low interface level queue

!

map-class frame-relay SHAPE_256K_LOW

 frame-relay cir 256000

 frame-relay bc 2560

 frame-relay be 0

 !

 ! Per-VC fancy-queueing

 !

 frame-relay fair-queue

 frame-relay interface-queue priority low
!

! Enable PIPQ as interface queueing strategy

!

interface Serial 0/0/0:0

 frame-relay traffic-shaping

 frame-relay interface-queue priority

!

interface Serial 0/0/0:0.1

 ip address 177.0.112.1 255.255.255.0

 frame-relay interface-dlci 112

  class SHAPE_384K_HIGH

!

interface Serial 0/0/0:0.2

 ip address 177.0.113.1 255.255.255.0

 frame-relay interface-dlci 113

  class SHAPE_256K_LOW

Verfication: Check PVC interface-level priorities

Rack1R1#show frame-relay pvc 112
PVC Statistics for interface Serial0/0/0:0 (Frame Relay DTE)
DLCI = 112, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE = Serial0/0/0:0.1
  cir 384000    bc 3840      be 0         byte limit 480    interval 10

  mincir 192000    byte increment 480   Adaptive Shaping none

  pkts 1687      bytes 113543    pkts delayed 0         bytes delayed 0

  shaping inactive

  traffic shaping drops 0

  Queueing strategy: weighted fair

  Current fair queue configuration:

   Discard     Dynamic      Reserved

   threshold   queue count  queue count

    64          16           0

  Output queue size 0/max total 600/drops 0

  priority high

  ^^^^^^^^^^^^^
Rack1R1#show frame-relay pvc 113
PVC Statistics for interface Serial0/0/0:0 (Frame Relay DTE)
DLCI = 113, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE = Serial0/0/0:0.2
  cir 256000    bc 2560      be 0         byte limit 320    interval 10

  mincir 128000    byte increment 320   Adaptive Shaping none

  pkts 1137      bytes 79691     pkts delayed 0         bytes delayed 0

  shaping inactive

  traffic shaping drops 0

  Queueing strategy: weighted fair

  Current fair queue configuration:

   Discard     Dynamic      Reserved

   threshold   queue count  queue count

    64          16           0

  Output queue size 0/max total 600/drops 0

  priority low

  ^^^^^^^^^^^^

Verify interface-level queue:

Rack1R1#show interfaces serial 0/0/0:0 | inc (Output|high)

  Output queue (queue priority: size/max/drops):

     high: 0/20/0, medium: 0/40/0, normal: 0/60/0, low: 0/80/0

- With FRF.12 fragmentation configured per any PVC, physical interface queue is changed to dual-FIFO
- This is due to the fact that fragmentation is ineffective without interleaving
- Fragment size is calculated based on physical interface speed to allow minimum serialization delay

Example: Enable FRF.12 fragmentation for PVC DLCI 112 and physical interface speed 512Kbps

!

! PVC shaped to 384Kbps, with physical interface speed 512Kbps

!

map-class frame-relay SHAPE_384K_FRF12

 frame-relay cir 384000

 frame-relay bc 3840

 frame-relay be 0

 !

 ! Per-VC fancy-queueing

 !

 frame-relay fair-queue
 !

 ! Enable FRF.12 per VC. Fragment size = 512Kbps*0,01/8 = 640 bytes

 !

 frame-relay fragment 640

!

!

!

interface Serial 0/0/0:0

 frame-relay traffic-shaping

!

interface Serial 0/0/0:0.1

 ip address 177.0.112.1 255.255.255.0

 frame-relay interface-dlci 112

  class SHAPE_384K_FRF12

Verfication: Check PVC settings

Rack1R1#show frame-relay pvc 112
PVC Statistics for interface Serial0/0/0:0 (Frame Relay DTE)
DLCI = 112, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE = Serial0/0/0:0.1
  fragment type end-to-end fragment size 640

  cir 384000    bc   3840      be 0         limit 480    interval 10

  mincir 192000    byte increment 480   BECN response no  IF_CONG no

  frags 1999      bytes 135126    frags delayed 0         bytes delayed 0

  shaping inactive

  traffic shaping drops 0

  Queueing strategy: weighted fair

  Current fair queue configuration:

   Discard     Dynamic      Reserved

   threshold   queue count  queue count

    64          16           0

  Output queue size 0/max total 600/drops 0

Look at physical interface queue:

Rack1R1#show interfaces serial 0/0/0:0 | inc Queu|Output q

  Queueing strategy: dual fifo

  Output queue: high size/max/dropped 0/256/0

  Output queue: 0/128 (size/max)

- You can map up to 4 priority queues to 4 different VCs (inverse PIPQ)
- This scenario usually implies multiple PVCs running between two sites (e.g. PVC for voice and PVC for data)

Example: Map voice packets to high interface-level priority queue and send them over PVC 112

!

! Voice bearer

!

access-list 101 permit udp any any range 16384 32767
!

! Simple priority list to classify voice bearer to high queue

!

priority-list 1 protocol ip high list 101
interface Serial 0/0/0:0

 ip address 177.1.0.1 255.255.255.0

 !

 ! We apply the priority group twice: first to implement queueing

 !

 priority-group 1

 !

 ! Next to map priority levels to DLCIs

 !

 frame-relay priority-dlci-group 1 112 112 113 113

Verfication:

Rack1R1#show queueing interface serial 0/0/0:0

Interface Serial0/0/0:0 queueing strategy: priority
Output queue utilization (queue/count)

	high/217 medium/0 normal/1104 low/55 
Rack1R1#show frame-relay pvc 112
PVC Statistics for interface Serial0/0/0:0 (Frame Relay DTE)
DLCI = 112, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE = Serial0/0/0:0
  pvc create time 3d01h, last time pvc status changed 3d01h

  Priority DLCI Group 1, DLCI 112 (HIGH), DLCI 112 (MEDIUM)

  DLCI 113 (NORMAL), DLCI 113 (LOW)

- You can change per-VC queue to CBWFQ/LLQ, and still shape with FRTS
- Note that available bandwidth will be calculated from minCIR value, which is CIR/2 by default

Example: Implement CBWFQ Per-VC

!

! Classify voice using NBAR

!

class-map VOICE

 match protocol rtp
!

! Simple LLQ

!

policy-map CBWFQ

 class VOICE

  priority 64

 class class-default

  bandwidth 64
!

! Use CBWFQ as queueing strategy

! Note that MinCIR = 384/2=192Kbps

!

map-class frame-relay SHAPE_384K_CBWFQ

 frame-relay cir 384000

 frame-relay bc 3840

 frame-relay be 0

 service-policy output CBWFQ

!

!

!

interface Serial 0/0/0:0

 frame-relay traffic-shaping

!

interface Serial 0/0/0:0.1

 ip address 177.0.112.1 255.255.255.0

 frame-relay interface-dlci 112

  class SHAPE_384K_CBWFQ

Verfication: Check PVC queueing strategy

Rack1R1#show frame-relay pvc 112
PVC Statistics for interface Serial0/0/0:0 (Frame Relay DTE)
DLCI = 112, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE = Serial0/0/0:0
  cir 384000    bc 3840      be 0         byte limit 480    interval 10

  mincir 192000    byte increment 480   Adaptive Shaping none

  pkts 0         bytes 0         pkts delayed 0         bytes delayed 0

  shaping inactive

  traffic shaping drops 0

  service policy CBWFQ

 Serial0/0/0:0: DLCI 112 -
  Service-policy output: CBWFQ
    Class-map: VOICE (match-all)

      0 packets, 0 bytes

      5 minute offered rate 0 bps, drop rate 0 bps

      Match: protocol rtp

      Queueing

        Strict Priority

        Output Queue: Conversation 40

        Bandwidth 64 (kbps) Burst 1600 (Bytes)

        (pkts matched/bytes matched) 0/0

        (total drops/bytes drops) 0/0
    Class-map: class-default (match-any)

      32 packets, 2560 bytes

      5 minute offered rate 0 bps, drop rate 0 bps

      Match: any

      Queueing

        Output Queue: Conversation 41

        Bandwidth 128 (kbps) Max Threshold 64 (packets)

        (pkts matched/bytes matched) 0/0

        (depth/total drops/no-buffer drops) 0/0/0

  Output queue size 0/max total 600/drops 0

To verify that only MinCIR of bandwidth is allocated to CBWFQ under map-class do the following:

Rack1R1(config)#policy-map CBWFQ

Rack1R1(config-pmap)# class VOICE

Rack1R1(config-pmap-c)#  priority 64

Rack1R1(config-pmap-c)# class class-default

Rack1R1(config-pmap-c)#  bandwidth 192

I/f Serial0/0/0:0 DLCI 112 Class class-default requested bandwidth 192 (kbps) Only 128 (kbps) available