Enterasys csx150 Betriebsanweisung

USER’S GUIDE

394      CyberSWITCH

3.

Verify that the device to which the connection is being established has compression enabled. If 
the 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 is 
typically accomplished by issuing the 

trace ppp on

 command, erasing the log contents, 

establishing the call, and then examining the log again (by issuing the 

dr

 console command) to 

view the frame trace.

The following traces illustrate some common PPP startup scenarios when compression is 
enabled. Only the CCP frames are excerpted for clarity.

As a reference, the following trace illustrates a successful negotiation of CCP using the Stac 

compression protocol. The key feature of this sequence is that each side receives a 
CONFIG-ACK to its respective CONFIG-REQ. 

If the peer does not actually support PPP compression, it will most likely Protocol-Reject 

the CyberSWITCH’s attempt to negotiate CCP. In this case, the CyberSWITCH will 
abandon 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 the 
trace indicate the CCP protocol (0x80FD).

In this case, the CyberSWITCH will respond to all attempts by the peer to open CCP with 

a TERM-ACK frame. The connection will operate uncompressed. (Note: a device that 
supports compression but has it disabled will typically do the exact same thing).

(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 

(I) 15:36:40.54 #80FD: Conn=001 IN -PPP:CCP      CFG REQ Id=0xEC Len=9
(I) 15:36:40.54 #9999: -Alg: 0x11 (STAC-LZS) Len: 5
(I) 15:36:40.54 #9999:   Hist Count: 01   Chk Mode: 0x03 (SEQ#)
(I) 15:36:40.54 #80FD: Conn=001 OUT-PPP:CCP      TERM ACK Id=0xEC Len=4