CTCP Configuration command Directory

debug ip tcp header-compression

ip tcp compression-connections

ip tcp header-compression

show ip tcp header-compression

 

This chapter describes CRTP commands. CRTP is used on the low-speed serial linkage. The command can be used for compressing the header of TCP/IP packet to effectively lower the occupation of bandwidth. At the same time, due to the reduction in packet length, the delay of packet transit on the linkage can be shortened substantially. CTCP is especially useful in employing the interactive protocol of TELNET kind with good response speed

 

debug ip tcp header-compression

[no] debug ip tcp header-compression

command mode:

global configuration mode

example:

Router#debug ip tcp h

TCP header compression debug is enalbed!

22:17:02: THC Serial1/0: new connection, conn 0

22:17:02: THC Serial1/0: output uncompressed, conn 0, cksum 0xA286, seq 95270092

22:17:02: THC Serial1/0: output COMPRESSED_TCP, conn 0, cksum 0x9F7D, seq 952702

22:17:02: THC Serial1/0: recv uncompressed, conn 0, cksum 0xA17F, seq 1220171780

22:17:02: THC Serial1/0: output uncompressed, conn 0, cksum 0xA283, seq 95270095

22:17:02: THC Serial1/0: recv COMPRESSED_TCP, conn 0, cksum 0x24CC, seq 12201713

22:17:02: THC Serial1/0: output COMPRESSED_TCP, conn 0, cksum 0xA283, seq 952705

The form below describes the explanation of the output of CTCP debug command

Area

Explanation

22:17:02

Current time of system

THC

TCP header compression

Serial 1/0

Interface number

Recv(output)

Input or output

COMPRESSED_TCP uncompressed)

Packet Type

Conn

Connection number

Cksum

UDP check sum

Seq

Sequence number of RTP

 

 

ip tcp header-compression

The command needs to be used under interface configuration mode for activating CTCP on serial linkage. The no format of the command needs to be used for forbidding CTCP.

ip tcp header-compression [{iphc-format | passive}]

no ip tcp header-compression

parameter:

iphc-format  (optional) obeying CTCP protocol of rfc2507 IPHC standard.  

passive   (optional) CTCP packet started to be sent after CTCP packet of opposite terminal is received.

default:

It is under forbidden state without configuring the command. When the command is configured, the default value is iphc-format iphc-format in the case of not adding optional parameters.

command mode:

interface configuration mode

explanation:

Currently CRTP is supported only on the serial linkage of PPP encapsulation and will be extended to Frame Relay、HDLC and ISDN port, etc. The command should be configured simultaneously on the two terminals of serial linkage, otherwise it will not work. Meanwhile, when the relative header of effective load of packet is relatively small, this protocol is quite applicable. However, when the header is far below net load, it will reversely add the processing spending of the router for the packet. Therefore, the protocol is used for transmitting the similar RPT packet on the linkage.

If CRTP is configured in our CTCP implementation, CRTP and TCP/IP header compression that is based on IPHC format of rfc2507 will be applied at the same time in spite of whether TCP/IP header compression is configured or not later. Therefore, if the opposite terminal only supports the terminal of TCP/IP header compression standards stipulated by rfc1144, it is not able to communicate. In addition, TCP/IP header compression shall be configured on the condition that CRTP is not configured to the local terminal. In PPP protocol, if the opposite terminal request TCP/IP header compression negotiation regulated by rfc2507, it will pass and support TCP/IP header compression regulated by CRTP and rfc2507. Otherwise, TCP/IP header compression standards stipulated by rfc1144.

Example:

Router_config#interface serial 1/2

Router_config_s1/2#ip tcp header-compression

 

ip tcp compression-connections

ip tcp compression-connections number

no ip tcp compression-connections

parameter:

number Maximum number of CTCP connection, the scope is 3-256, the default value is 16.

default:

16 connections

command mode:

interface configuration mode

explanation:

The number of TCP/IP dialogue that is likely to occur simultaneously in the linkage can be estimated under general condition. It will right when the number of configured connection is bigger than the number of TCP/IP dialogue.

Example:

Router_config#interface serial 1/2

Router_config_s1/2#ip tcp header-compression

Router_config_s1/2#ip tcp compression-connections 25

Router_config_s1/2#enc ppp

Router_config_s1/2#

 

show ip tcp header-compression

show ip tcp header-compression [type number] [detail]

parameter:

type number (optional) Interface type and interface number, such as serial 1/2

detail    (optional) Showing detailed information of each linkage

 

command mode:

global configuration mode

example:

Router#sh ip tcp header-compression

IP/TCP header compression statistics:

Interface Serial1/0:

Rcvd:           8900 total, 8858 compressed, 0 errors

                0 dropped, 0 buffer copies, 0 buffer failures

Sent:           8907 total, 8865 compressed,

                336735 bytes saved, 197685 bytes sent

Connect: 16 rx slots, 16 tx slots, 15 long searches, 1 misses

Router#

Keyword explanation of command display is made in the form below

Keyword

Explanation

Interface Serial1/0:

Interface number and interface type

Rcvd: total

Total of CRTP packet received at the port.

compressed

Total of compressed CTCP packet

errors

Total of erroneous packet received.

dropped

Total of directly deleted packet received.

buffer copies,

The number of the packet that should be copied and saved.

buffer failures

The number of failures of applying for memory at the time of restoring normal IP packet.

Sent: total

Total of CTCP packet sent.

compressed

Total of compressed CTCP packet sent.

bytes saved

Saved bytes

bytes sent

Real number of bytes sent

Connect: rx slots

Total of data structure received

tx slots

Total of data structure sent

long searches

It is needed to search in transmit data structure so as to determine the number of which to be used.

Misses

Search the number of failure of data structure.