IPCP, PPP Internet Protocol Control Protocol

Description Glossary RFCs Publications Obsolete RFCs


Protocol suite: PPP.
Protocol type:PPP network control protocol.
PPP protocol:0x8021.
Working groups: pppext, Point-to-Point Protocol Extensions.
Links: IANA: PPP Assigned numbers.

The IPCP protocol is used to establish and configure the IP protocol over PPP links.

RFC 1332:

This document defines the NCP for establishing and configuring the Internet Protocol over PPP and a method to negotiate and use the Van Jacobson TCP/IP header compression with PPP.

IPCP is responsible for configuring, enabling, and disabling the IP protocol modules on both ends of the point-to-point link. IPCP uses the same packet exchange mechanism as the Link Control Protocol (LCP). IPCP packets may not be exchanged until PPP has reached the Network-Layer Protocol phase. IPCP packets received before this phase is reached should be silently discarded.

Before any IP packets may be communicated, PPP must reach the Network-Layer Protocol phase, and the IP Control Protocol must reach the Opened state.

Van Jacobson TCP/IP header compression reduces the size of the TCP/IP headers to as few as three bytes. This can be a significant improvement on slow serial lines, particularly for interactive traffic.

The IP Compression Protocol Configuration Option is used to indicate the ability to receive compressed packets. Each end of the link must separately request this option if bidirectional compression is desired.

The Max Slot Id field indicates the maximum slot identifier.

PPP header IPCP header Data :::

IPCP header:

0001020304050607 0809101112131415 1617181920212223 2425262728293031
Code Identifier Length
Data :::

Code. 8 bits.
Specifies the function to be performed.

0Vendor Specific. RFC 2153

Identifier. 8 bits.
Used to match requests and replies.

Length. 16 bits.
Size of the packet including the header.

Data. Variable length.
Zero or more bytes of data as indicated by the Length. This field may contain one or more Options.

IPCP Configuration Options:

0001020304050607 0809101112131415
Option Length
Data :::

Option. 8 bits.

1 IP-Addresses (deprecated). RFC 1332
2>= 14IP-Compression-Protocol. RFC 1332, RFC 3241, RFC 3544
3 6IP-Address. RFC 1332
46Mobile-IPv4. RFC 2290
1296Primary DNS Server Address. RFC 1877
1306Primary NBNS Server Address. RFC 1877
1316Secondary DNS Server Address. RFC 1877
1326Secondary NBNS Server Address. RFC 1877

Length. 8 bits.

Data. Variable length.



[RFC 1332] The PPP Internet Protocol Control Protocol (IPCP).

[RFC 1716] Towards Requirements for IP Routers.

[RFC 1812] Requirements for IP Version 4 Routers.

[RFC 1877] PPP Internet Protocol Control Protocol Extensions for Name Server Addresses.

[RFC 2290] Mobile-IPv4 Configuration Option for PPP IPCP.

[RFC 2794] Mobile IP Network Access Identifier Extension for IPv4.

[RFC 3241] Robust Header Compression (ROHC) over PPP.

[RFC 3544] IP Header Compression over PPP.


Obsolete RFCs:

[RFC 1134] The Point-to-Point Protocol: A Proposal for Multi-Protocol Transmission of Datagrams Over Point-to-Point Links.

[RFC 1171] The Point-to-Point Protocol for the Transmission of Multi-Protocol Datagrams Over Point-to-Point Links.

[RFC 1172] The Point-to-Point Protocol (PPP) Initial Configuration Options.

[RFC 2509] IP Header Compression over PPP.

Description Glossary RFCs Publications Obsolete RFCs