In computer networking, Internet Protocol Control Protocol (IPCP) is a network control protocol for establishing and configuring Internet Protocol over a Point-to-Point Protocol link. IPCP uses the same packet exchange mechanism as the Link Control Protocol. IPCP packets may not be exchanged until PPP has reached the Network-Layer Protocol phase, and any IPCP packets received before this phase is reached should be silently discarded.
Contents |
After the configuration is done, the link is able to carry IP data as a payload of the PPP frame. This code indicates that IP data is being carried.
| PPP header | IPCP header | Data ::: |
IPCP header:
| 00 | 01 | 02 | 03 | 04 | 05 | 06 | 07 | 08 | 09 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Code | Identifier | Length | |||||||||||||||||||||||||||||
| Data ::: | |||||||||||||||||||||||||||||||
Code.
8 bits.
Specifies the function to be performed.
| Code | Description | References |
|---|---|---|
| 0 | Vendor Specific. | RFC 2153 |
| 1 | Configure-Request. | |
| 2 | Configure-Ack. | |
| 3 | Configure-Nak. | |
| 4 | Configure-Reject. | |
| 5 | Terminate-Request. | |
| 6 | Terminate-Ack. | |
| 7 | Code-Reject. |
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 allow negotiatiation of desirable Internet Protocol parameters. IPCP uses the same Configuration Option format defined for LCP Link Control Protocol, with a separate set of Options.
IPCP Configuration Options:
| 00 | 01 | 02 | 03 | 04 | 05 | 06 | 07 | 08 | 09 | 10 | 11 | 12 | 13 | 14 | 15 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Option | Length | ||||||||||||||
| Data ::: | |||||||||||||||
Option. 8 bits.
| Option | Length | Description | References |
|---|---|---|---|
| 1 | IP-Addresses (deprecated). | RFC 1332 | |
| 2 | >= 14 | IP-Compression-Protocol. |
RFC 1332, RFC 3241, RFC 3544 |
| 3 | 6 | IP-Address. | RFC 1332 |
| 4 | 6 | Mobile-IPv4. | RFC 2290 |
| 129 | 6 | Primary DNS Server Address. | RFC 1877 |
| 130 | 6 | Primary NBNS Server Address. | RFC 1877 |
| 131 | 6 | Secondary DNS Server Address. | RFC 1877 |
| 132 | 6 | Secondary NBNS Server Address. | RFC 1877 |
Length. 8 bits.
Data. Variable length.
| Type | Length | IP-Compression-Protocol | Data |
|---|---|---|---|
| 1 byte | 1 byte | 2 bytes | variable |
| Type | Length | IP address |
|---|---|---|
| 1 byte | 1 byte | 4 bytes |