3. Operation3160-A2-GB21-90 February 2001 3-23Selecting the Link Layer ProtocolTwo link layer protocols, Point-to-Point Protocol (PPP) and Serial Line InternetProtocol (SLIP), are supported for connection to an external SNMP manager,Telnet device, or network device (e.g., a router). PPP can be used for synchronousor asynchronous operation. SLIP can be used for asynchronous operation only.NOTE:The carrier-mounted DSU/CSU does not support synchronous operation onthe COM port.The standalone DSU/CSU implementation of PPP supports the following: Full negotiation of PPP’s Link Control Protocol (LCP). Active negotiation of LCP when the connection is established. Maximum Request Unit (MRU) sizes up to 1500 bytes, but the DSU/CSU willattempt to negotiate down to 500 bytes. The DSU/CSU provides a unique LCP magic number derived from the unitserial number and the elapsed time. Full negotiation of escape characters.The DSU/CSU implementation of PPP does not support Link Quality Reports(LQR), compression, encryption, Password Authentication Protocol (PAP) orChallenge Handshake Authentication Protocol (CHAP).The DSU/CSU implementation of SLIP supports a fixed MRU size of 1006 bytes.Before selecting the protocol, you must first select the port to be used as thecommunications link. Refer toSelecting the Port on page 3-20. This exampleassumes that the COM port is being used as the communications link.ProcedureTo select the link layer protocol:1. From the top-level menu screen, select Cnfig.2. Select the configuration option set to be copied into the Edit area by using theappropriate Function key. Use the scroll keys, if necessary.3. Select Edit.4. From the Edit screen, press the key until the Mgmt selection appears onthe screen.
