The customer has two Comten Front End Processors -- one in the USA and the other in France. The customer would like to connect them via Cisco routers. Initial setup was to use stun route all. This was unsuccessful as the FEPs were constantly timing out. One of the Comten FEPs was not retrying the number of times it was configured for. Consequently, the sessions timed out. The customer decided to use local-ack upon recommendation by Cisco.
The following is a sample configuration for FEP to FEP using local-ack.
System Image 9.1.8 and above is required.
- - - - - FEP ---- 19.2 -S1- 4000 -E0-- IP CLOUD --E0- 4000 -S2- 19.2 ---- FEP F_Sec R_Pri - - R_Sec F_Pri - - -
FEP - Front End Processor (37X5) 4000 - Cisco 4000 Router F_Pri - FEP acting as primary F_Sec - FEP acting as secondary R_Pri - Router acting as primary R_Sec - Router acting as secondary Sx - Serial Port x Ex - Ethernet Port x
Current configuration: version 9.1 ! hostname ROUTER_PRIMARY ! ! boot system flash xx-k.91-8.2.Z boot system rom ! ! buffers big min-free 10 buffers large max-free 40 buffers large min-free 20 ! ! stun peer-name 161.131.40.1 stun remote-peer-keepalive stun protocol-group 1 sdlc-tg ! ! interface Ethernet 0 ip address 161.131.40.1 255.255.255.0 no mop enabled ! ! interface Serial 1 mtu 4400 no ip address hold-queue 150 in encapsulation stun stun group 1 stun sdlc-role primary sdlc line-speed 19200 sdlc n1 35200 sdlc address 04 echo stun route address 4 tcp 156.28.11.1 local-ack clockrate 19200
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Current configuration: version 9.1 ! hostname ROUTER_SECONDARY ! ! boot system flash xx-k.91-8.2 boot system rom ! ! buffers big min-free 10 buffers large max-free 40 buffers large min-free 20
stun peer-name 156.28.11.1 stun remote-peer-keepalive stun protocol-group 1 sdlc-tg ! ! interface Ethernet 0 ip address 156.28.11.1 255.255.255.0 no mop enabled ! ! interface Serial 2 mtu 4400 no ip address hold-queue 150 in encapsulation stun stun group 1 stun sdlc-role secondary sdlc n1 35200 sdlc address 04 echo stun route address 4 tcp 161.131.40.1 local-ack
stun remote-peer-keepalive [secs]
For synchronization of peers the default is 30 seconds, and three attempts. This is only sent when there is no I-Frame traffic between NCPs.
stun protocol-group [number] sdlc-tg
This has to be enabled for a SDLC broadcast address, such as xFF. This also performs the TG reroute function and must be used with local-ack.
MTU [number]
Specify MTU greater than NCPs max data MTU (buffers*transfer, maxdata). 4400 is the highest recommended for stun interface.
sdlc n1 [number]
Required if MTU is not 1500 and recommended to be eight times MTU.
hold-queue [number] in
Increases the hold queue from 75 to 150.
sdlc line-speed [number]
This is for the SDLC Primary Router and poll-timer adjustment. Set it to the line speed of stun interface. (DTE or DCE)
sdlc address [number] echo
Echo treats non-echo (eg. x04) and echo (eg. x84) as the same addresses. It is only valid for sdlc-tg interfaces. Only one sdlc address with echo option per interface is required.
stun route address [number] tcp [ip address] local-ack
Local-ack and TCP must be specified for sdlc-tg. Specify the address number with echo bit off (eg. x04). There is no need to specify broadcast address (xFF).
clockrate
This is only for DCE. Also, use the transmit-clock-internal for 7000.
They must be tuned for 4000 and 7000 platforms for stun. Contact the Technical Assistance Center.
When tuning buffers, administratively shut down the stun interface first.
stun cos-enable
For SNA network prioritization - Class of Service. This must be used in conjunction with priority keyword on stun route ...
priority-list [number] priority-group [list]
Priority-queuing mechanism.
Administratively shut down the stun interfaces while configuring for priority-queuing.
Sh int s 2 (stun secondary interface)
Serial 2 is up, line protocol is up Hardware is MK5025 Description: Router_Secondary MTU 4400 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 1/255 This end is the secondary station. Poll Timers (msec): wait 40000 [N1 35200, K 7] timer: 66421396
--More SDLC information for this interface--
SDLC addr 4 state is CONNECT VS 1, VR 1, RCNT 0, Remote VR 1, Current retransmit count 0 Hold queue: 0/50 IFRAMEs 247/255 RNRs 0/0 SNRMs 0/106 DISC/RDs 0/0 REJs 0/0 chain: 04/04 Last input 0:01:05, output 0:00:00, output hang never Last clearing of "show interface" counters 0:00:27 Output queue 0/40, 0 drops; input queue 0/150, 0 drops Five minute input rate 0 bits/sec, 5 packets/sec Five minute output rate 0 bits/sec, 5 packets/sec 137 packets input, 274 bytes, 0 no buffer Received 0 broadcasts, 0 runts, 0 giants 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort 137 packets output, 274 bytes, 0 underruns 0 output errors, 0 collisions, 0 interface resets, 0 restarts 0 carrier transitions
Router_Secondary#sh stun
This peer: 156.28.11.1
*Serial2 -- Internet/LS transfix 19.2kbs (group 1 [sdlc-tg]) state l rx_pkts tx_pkts drops poll 4 TCP 161.131.40.1 open * 3387 12487 297
SDLC Local Acknowledgement:
Serial2 -- Internet/LS transfix 19.2kbs (group 1 [sdlc-tg]) slack_state conn disc iframe_s iframe_r 4 TCP 161.131.40.1 Active 7 209 247 255
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Router_Primary#sh stun
This peer: 161.131.40.1
*Serial1 (group 1 [sdlc-tg])
state l rx_pkts tx_pkts drops poll 4 TCP 156.28.11.1 open * 680 823 0
SDLC Local Acknowledgement:
*Serial1 (group 1 [sdlc-tg]) slack_state conn disc iframe_s iframe_r 4 TCP 156.28.11.1 Active 96 189 152 153