Cabletron Systems CSX1200 User Manual

Also see for CyberSWITCH CSX1000: User guide Quick start

Contents

USER’S GUIDE412 CyberSWITCHC OMPRESSIONProblem:Compression is not established for a device for which it is expected.Action:1. Issue thecmp stats console command then issue thedr console command to check themessage report log. A message will inform you if the compression failed due to memoryconstraints.2. Verify that the CyberSWITCH has compression enabled. This is done through selecting“Compression Options” from CFGEDIT’s Systems Options menu.3. Verify that the device to which the connection is being established has compression enabled. Ifthe device is another CyberSWITCH, refer to the previous step for instructions.4. Use the trace console command to examine the CCP frames exchanged with the device. This istypically accomplished by issuing thetrace ppp on command, erasing the log contents,establishing the call, and then examining the log again (by issuing thedr console command) toview the frame trace.The following traces illustrate some common PPP startup scenarios when compression isenabled. Only the CCP frames are excerpted for clarity.• Successful NegotiationAs a reference, the following trace illustrates a successful negotiation of CCP using the Staccompression protocol. The key feature of this sequence is that each side receives aCONFIG-ACK to its respective CONFIG-REQ.• Peer Protocol-Rejects CCPIf the peer does not actually support PPP compression, it will most likely Protocol-Rejectthe CyberSWITCH’s attempt to negotiate CCP. In this case, the CyberSWITCH willabandon its attempt to use compression and the connection will operate uncompressed.The incoming frame from the peer contains a PROT-REJ, whose 1st two hex octets in thetrace indicate the CCP protocol (0x80FD).(I) 15:35:09.98 #80FD: Conn=001 OUT-PPP:CCP CFG REQ Id=0xB4 Len=9(I) 15:35:09.98 #9999: -Alg: 0x11 (STAC-LZS) Len: 5(I) 15:35:09.98 #9999: Hist Count: 01 Chk Mode: 0x03 (SEQ#)(I) 15:35:09.98 #80FD: Conn=001 IN -PPP:CCP CFG REQ Id=0x7B Len=9(I) 15:35:09.98 #9999: -Alg: 0x11 (STAC-LZS) Len: 5(I) 15:35:09.98 #9999: Hist Count: 01 Chk Mode: 0x03 (SEQ#)(I) 15:35:09.99 #80FD: Conn=001 OUT-PPP:CCP CFG ACK Id=0x7B Len=9(I) 15:35:09.99 #9999: -Alg: 0x11 (STAC-LZS) Len: 5(I) 15:35:09.99 #9999: Hist Count: 01 Chk Mode: 0x03 (SEQ#)(I) 15:35:09.99 #80FD: Conn=001 IN -PPP:CCP CFG ACK Id=0xB4 Len=9(I) 15:35:09.99 #9999: -Alg: 0x11 (STAC-LZS) Len: 5(I) 15:35:09.99 #9999: Hist Count: 01 Chk Mode: 0x03 (SEQ#)(I) 16:01:51.65 #80FD: Conn=001 OUT-PPP:CCP CFG REQ Id=0x87 Len=9(I) 16:01:51.65 #9999: -Alg: 0x11 (STAC-LZS) Len: 5(I) 16:01:51.65 #9999: Hist Count: 01 Chk Mode: 0x03 (SEQ#)(I) 16:01:51.65 #C021: Conn=001 IN -PPP:LCP PROT REJ Id=0x00 Len=15(I) 16:01:51.71 #0000: 80 FD 01 87 00 09 11 05 00 01 03