- Enterasys Security Router User's Guide

Utilizing the Command Line Interface
2-16 Managing the XSR
CLI Command Limits
CLI commands on the XSR are bounded by the following:
• Total number of characters in a command line/help message: 299
• Total number of words in a command line: 127
• Number of command history entries recalled: 31
• Total number of characters in a prompt: 1023
• Total number of characters in system name: 31
Describing Ports and Interfaces
Technically, a port is a physical connector with some physical layer values. XSR ports are:
FastEthernet (XSR 1800 Series) or GigabitEthernet (XSR 3000 Series), Async/Sync Serial, ATM,
BRI, Loopback, T1/E1T3/E3, Console, and Null. An interface is a data and management plane
comprising the physical, link and a part of the network layer. The terms are used interchangeably
in this manual. The XSR supports multiple access types, including Fast/GigabitEthernet LAN,
Frame Relay and Serial WAN access over Asynchronous, Synchronous, T1/E1, and Serial lines
with async and sync access over permanent or dial lines. Generally, Frame Relay, PPP and
Multilink PPP (Console optional) are for WAN access and PPPoE for WAN access over a LAN.
Dial access is provided by ISDN BRI and PRI.
Supported Physical Interfaces
The XSR supports the following physical interfaces:
• FastEthernet/GigabitEthernet for LAN port consisting of Ethernet's physical, Mac (Layer-2), and
IP layer functionality.
• Serial for Sync or Async port/line consisting of a Sync port/line's physical, Layer-2 (PPP) and IP
layer functionality.
• Serial for T1/E1 (PRI) channel group consisting of its physical, Layer-2 (PPP or Frame Relay),
and IP layer functionality.
Supported Virtual Interfaces
The XSR supports the following virtual interfaces:
• Interface dialer includes physical interfaces supporting dial connectivity from the dial port/
line's physical layer functionality including dialing, Layer-2 (PPP), and IP layer functionality.
• Sub-Interface for an NBMA network. An NBMA network has multiple access over the same
line but no broadcast capability. Examples of such networks are Frame Relay, X.25, and ATM.
One physical interface comprises one or more sub-interfaces which in turn consist of one or
more circuits on the physical interface. Sub-interface examples and its circuits are: one or more
DLCIs forming a sub-interface, one or more X.25 PVC/SVCs forming a sub-interface and one
or more VCs of ATM forming a sub-interface. This interface shares its physical layer
functionality with other sub-interfaces, but each sub-interface has its own layer-2 (PPP or
Frame Relay) and IP layer functionality.