XNSCP, PPP XNS IDP Control Protocol

Description Glossary RFCs Publications Obsolete RFCs


Protocol suite: PPP.
Protocol type:PPP network control protocol.
PPP protocol:0x8025.
MIME subtype:
Working groups: pppext, Point-to-Point Protocol Extensions.

The XNSCP protocol is used for establishing, configuring and disabling the Xerox Network Systems (XNS) Internet Datagram Protocol (IDP) over PPP.

RFC 1764:

In order to establish communications over a point-to-point link, each end of the PPP link must first send LCP packets to configure and test the data link. After the link has been established and optional facilities have been negotiated as needed by the LCP, PPP must send XNSCP packets to choose and configure the XNS IDP network-layer protocol. Once XNSCP has reached the Opened state, XNS IDP datagrams can be sent over the link.

The link will remain configured for communications until explicit LCP or XNSCP packets close the link down, or until some external event occurs (an inactivity timer expires or network administrator intervention).

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

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

PPP header XNSCP header Data :::

XNSCP 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.

0Vendor Specific. RFC 2153
2 Configure-Ack.  
3 Configure-Nak.  
4 Configure-Reject.  
5 Terminate-Request.  

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

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

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



[RFC 1764] The PPP XNS IDP Control Protocol (XNSCP).


Obsolete RFCs:

Description Glossary RFCs Publications Obsolete RFCs