RE: MQC-based FRTS & dual FIFO

From: Alexander Arsenyev (GU/ETL) (alexander.arsenyev@ericsson.com)
Date: Thu Jan 06 2005 - 07:17:25 GMT-3


Hello,

- Routing protocol traffic queueing depends on platform, configuration (7500 series), packet type (OSPF HELLO is marked with pak_priority, other OSPF packets are not) and IOS version
http://www.cisco.com/warp/public/105/rtgupdates.html
http://www.cisco.com/univercd/cc/td/doc/product/software/ios120/120newft/120limit/120s/120s28/12sclocp.htm
 
- Have You enabled "frame-relay fragment 80" on both ends of the PVC?
If not then remote router won't attempt to reassemble FRF.12 fragments
because it doesn't have FRF.12 enabled!
http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122cgcr/fqos_c/fqcprt5/qcfrsvfr.htm#1005211

HTH,
Cheers
Alex
#13405

-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]
Sent: 05 January 2005 21:18
To: ccielab@groupstudy.com
Subject: MQC-based FRTS & dual FIFO

- When using dual FIFO as a result of FRF.12 , control & voice packets get
placed in the high FIFO queue while the rest get fragmented & placed
in the second queue. If you set the fragment size too low, will routing
protocol traffic ( OSPF hellos ) be fragmented & placed in the secondary
queue ?

- Does routing protocol traffic get put into the llq by default due to
pakpriority or is this a L2 queuing process ?

- From the priority debug I assume 0 is the high & 2 is default ? ( In my
config I have a llq & class-default policy in a FRTS mapp-class )

*Mar 1 03:29:58.515: PQ: Serial0/0 output (Pk size/Q 49/0)
*Mar 1 03:29:58.519: PQ: Serial0/0 output (Pk size/Q 46/2)

- I noticed a strange behavior where L3 traffic ( ospf hellos, telnet )
were being dropped by using a low (<100) fragment setting.
Can someone explain this ?

  | | S0/0.1 __________________s0/0/.1 | |
  | R1 | | R2
|
  | | s0/0.2 ___________________s0/0.2 | |

R2

!
class-map match-all telnet
  match access-group 100
!
!
policy-map qos
  class telnet
   priority percent 5
policy-map shape
  class class-default
   shape average 1544000
   shape adaptive 768000
   service-policy qos

!
interface Serial0/0.1 point-to-point
 ip address 192.168.1.1 255.255.255.252
 frame-relay interface-dlci 100
  class dave
!
interface Serial0/0.2 point-to-point
 ip address 192.168.7.1 255.255.255.252
 frame-relay interface-dlci 400
!
map-class frame-relay dave
 service-policy output shape
 frame-relay fragment 80 ( not a realistic # for a T1 )
!
After enabling fragment in the map class on s0/0.1
R2
R2#sh ip ospf nei
Neighbor ID Pri State Dead Time Address Interface
1.1.1.1 0 FULL/ - 00:00:37 192.168.7.2 Serial0/0.2
1.1.1.1 0 INIT/ - 00:00:37 192.168.1.2 Serial0/0.1

Serial0/0 is up, line protocol is up
  Hardware is QUICC Serial
  MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec,
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation FRAME-RELAY, loopback not set
  Keepalive set (10 sec)
  LMI enq sent 252, LMI stat recvd 252, LMI upd recvd 0, DTE LMI up
  LMI enq recvd 0, LMI stat sent 0, LMI upd sent 0
  LMI DLCI 1023 LMI type is CISCO frame relay DTE
  Broadcast queue 0/64, broadcasts sent/dropped 618/0, interface
broadcasts 534
  Last input 00:00:00, output 00:00:00, output hang never
  Last clearing of "show interface" counters 00:42:07
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 1
  Queueing strategy: dual fifo
  Output queue: high size/max/dropped 0/256/0
  Output queue: 0/128 (size/max)

*** changed fragment from 80 to 1600

R2(config-map-class)#frame-relay fragment 1600
R2(config-map-class)#^Z
R2#
*Mar 1 00:46:49.223: %SYS-5-CONFIG_I: Configured from console by vty1
(192.168.
7.2)debug ip ospf
*Mar 1 00:46:51.267: %OSPF-5-ADJCHG: Process 100, Nbr 1.1.1.1 on
Serial0/0.1 fr
om LOADING to FULL, Loading Donea
*Mar 1 00:47:02.203: %OSPF-5-ADJCHG: Process 100, Nbr 33.33.33.33 on
Serial0/0.
1 from LOADING to FULL, Loading Doned

- Where do you see the most benefit from using the dual FIFO buffers (
given a BW > than 768k ) ?

Thanks !

Regards,
Dave
______________________________________________
Architecture & Engineering
Work: (973) 682-4435
Cell: (973)907-4963



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