CTCP Configuration command Directory
debug ip tcp header-compression
ip tcp compression-connections
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
global
configuration mode
Router#debug ip tcp h
TCP header compression debug is enalbed!
22:17:02: THC Serial1/0: new connection, conn 0
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 |
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
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.
interface
configuration mode
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 number
no ip tcp
compression-connections
number Maximum number of CTCP
connection, the scope is 3-256, the default value is 16.
16 connections
interface
configuration mode
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.
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 [type number] [detail]
type number (optional)
Interface type and interface number, such as serial 1/2
detail (optional)
Showing detailed information of each linkage
global
configuration mode
Router#sh ip tcp header-compression
IP/TCP header compression statistics:
Interface Serial1/0:
0 dropped, 0 buffer copies, 0 buffer failures
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. |