CCIE Pursuit Blog

April 29, 2008

Internetwork Expert Volume II: Lab 5 – Section 7

QoS – 8 Points

7.1 Frame Relay Traffic Shaping

We need to configure FRTS on r1.

AIR = 512Kbps
CIR = 384Kbps
MINCIR = 256Kbps
Be = Up to port speed
Tc = 100ms

We also know that we need to use adaptive shaping.

Bc = CIR * (Tc/1000)
Be = (AR – CIR) * (Tc/1000)

Adaptive Frame Relay Traffic Shaping for Interface Congestion

Frame-Relay Traffic Shaping

We can knock out the easy ones first:

map-class frame-relay FRTS
 frame-relay cir 384000
 frame-relay mincir 256000
 frame-relay adaptive-shaping becn

Now we just need to configure Bc and Be.

Bc = CIR * (Tc/100)
Bc = 384000 * (100/1000)
Bc = 384000 * .1
Bc = 38400

Be = (AR – CIR) * (Tc/1000)
Be = (512000 – 384000) * (100/1000)
Be = (128000) * (.1)
Be = 12800

So our final map-class is:

map-class frame-relay FRTS
 frame-relay cir 384000
 frame-relay bc 38400
 frame-relay be 12800
 frame-relay mincir 256000
 frame-relay adaptive-shaping becn

r1(config#int s0/0
r1(config-if)#frame traffic
r1(config-if)#frame interface-dlci 113
r1(config-fr-dlci)#class FRTS

r1(config-if)#do sh traffic

Interface   Se0/0
       Access Target    Byte   Sustain   Excess    Interval  Increment Adapt
VC     List   Rate      Limit  bits/int  bits/int  (ms)      (bytes)   Active
103           56000     875    7000      0         125       875       –
104           56000     875    7000      0         125       875       –
105           56000     875    7000      0         125       875       –
113           384000    6400   38400     12800     100       4800      BECN 
102           56000     875    7000      0         125       875       –

IE simply applies the map-class to the interface.  I don’t agree with their solution as all PVCs are affected and not just the PVC to r1.  Of course, only DLCI 113 is actually being used so…..ask your friendly proctor for clarification.  🙂

7.2 RTP Header Compression

Configure the Frame connection between r3 and r4 to support RTP header compression. 

ip rtp header-compression

r3’s s0/0 is a multipoint, physical Frame-Relay interface and we need to configure this only on the DLCI to r4.  I had to peek the answer on this one.

frame-relay map ip rtp header-compression

r3(config-if)# frame-relay map ip 162.1.0.4 304 rtp header-compression ?
  active            Always compress RTP headers
  connections       Maximum number of compressed RTP connections
  passive           Compress for destinations sending compressed RTP headers
  periodic-refresh  Send periodic refresh packets
  <cr>

Ummmm….did this blow away my broadcast capability

Before:
r3(config-if)#do sh run int s0/0:0 | i 162.1.0.4
 frame-relay map ip 162.1.0.4 304 broadcast

After:
r3(config-if)#do sh run int s0/0:0 | i 162.1.0.4
 frame-relay map ip 162.1.0.4 304 rtp header-compression passive connections 15

r3(config)#do sh frame map | sec 162.1.0.4
Serial0/0:0 (up): ip 162.1.0.4 dlci 304(0x130,0x4C00), static,
              CISCO, status defined, active
              RTP Header Compression (enabled), passive (enabled), connections: 15

Make sure that you leave your broadcast keyword in your map:

frame-relay map ip 162.1.0.4 304 broadcastrtp header-compression passive connections 15

Your connections need to match on both sides:

r4(config-if)#do sh run int s0/0 | i header
 frame-relay map ip 162.1.0.3 403 broadcast rtp header-compression connections 15

r3#sh ip rtp header-compression
RTP/UDP/IP header compression statistics:
 DLCI 304        Link/Destination info: ip 162.1.0.4
  Interface Serial0/0:0 DLCI 304 (compression off, Cisco, RTP, passive)
    Rcvd:    0 total, 0 compressed, 0 errors, 0 status msgs
             0 dropped, 0 buffer copies, 0 buffer failures
    Sent:    0 total, 0 compressed, 0 status msgs, 0 not predicted
             0 bytes saved, 0 bytes sent
    Connect: 15 rx slots, 15 tx slots,
             0 misses, 0 collisions, 0 negative cache hits, 15 free contexts

7.3 Bandwidth Limiting

“…Microsoft SQL traffic is limited to an average rate of 256Kbps on r2’s connection to the Frame Realy cloud.”
“Up to 2048 SQL packets in excess of 256Kbps should be queued up by r2 before packet loss occurs.”

Sounds like queueing to me.

“Do not use an access-list to accomplish this.”

That means we’ll be using a class-map with NBAR to match the traffic.

r2(config-cmap)#match protocol ?
—output truncated—
  sqlnet            SQL*NET for Oracle
  sqlserver         MS SQL Server

—output truncated—

We need to match on MICROSOFT SQL:

class-map match-all TASK_73
 match protocol sqlserver

r2(config-if)#policy-map TASK_73
r2(config-pmap)#class TASK_73
r2(config-pmap-c)#shape average 256000
r2(config-pmap-c)#shape ?
  adaptive        Enable Traffic Shaping adaptation to BECN
  average         configure token bucket: CIR (bps) [Bc (bits) [Be (bits)]],
                  send out Bc only per interval
  fecn-adapt      Enable Traffic Shaping reflection of FECN as BECN
  fr-voice-adapt  Enable rate adjustment depending on voice presence
  max-buffers     Set Maximum Buffer Limit
  peak            configure token bucket: CIR (bps) [Bc (bits) [Be (bits)]],
                  send out Bc+Be per interval

shape max-buffers

r2(config-pmap-c)#shape max-buffers 2048

r2(config-pmap-c)#int s0/0/0.1
r2(config-subif)#service-policy output TASK_73

r2(config-subif)#do sh policy-map int s0/0/0.1

 Serial0/0/0.1

  Service-policy output: TASK_73

    Class-map: TASK_73 (match-all)
      0 packets, 0 bytes
      5 minute offered rate 0 bps, drop rate 0 bps
      Match: protocol sqlserver
      Traffic Shaping
           Target/Average   Byte   Sustain   Excess    Interval  Increment
             Rate           Limit  bits/int  bits/int  (ms)      (bytes)
           256000/256000    1984   7936      7936      31        992

        Adapt  Queue     Packets   Bytes     Packets   Bytes     Shaping
        Active Depth                         Delayed   Delayed   Active
        –      0         0         0         0         0         no

    Class-map: class-default (match-any)
      23 packets, 2598 bytes
      5 minute offered rate 0 bps, drop rate 0 bps
      Match: any

 

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