Specifications

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Software Configuration Guide For Cisco 2600 Series, Cisco 3600 Series, and Cisco 3700 Series Routers
OL-1957-03
Chapter 1 Understanding Interface Numbering and Cisco IOS Software Basics
Understanding Interface Numbering
Note The number and type of interfaces vary depending on the router.
WAN and LAN Interface Numbering
The Cisco 2600 series router chassis contains the following wide-area network (WAN) and local-area
network (LAN) interface types:
• Built-in LAN interfaces: Ethernet, FastEthernet, Token Ring
• Two or three slots in which you can install WAN interface cards (WICs)
• One slot in which you can install a network module
The numbering format is Interface-type Slot-number/Interface-number. Two examples are:
Ethernet 0/0
Serial 1/2
The slot number is 0 for all built-in interfaces and 0 for all WIC interfaces; the slot number is 1 for
network module interfaces.
Interface (port) numbers begin at 0 for each interface type, and continue from right to left and (if
necessary) from bottom to top.
Figure 1-1 below shows a router of 1 RU height with:
• A WIC in each WIC slot (containing interface Serial 0/0 in physical slot W0, and interface
Serial 0/1 in physical slot W1)
• A 4-serial-port network module in slot 1 (containing the following ports: Serial 1/0, Serial 1/1,
Serial 1/2, and Serial 1/3)
• First built-in Ethernet interface—Ethernet 0/0
• Second built-in Ethernet interface—Ethernet 0/1, or optionally in Cisco 2612 and Cisco 2613 only:
Token Ring interface 0/0
Cisco 2650XM 1 1 2 1
Cisco 2651 2 1 2 1
Cisco 2651XM 2 1 2 1
Cisco 2691 2 1 3 2
Table 1-1 Summary of Cisco 2600 Series Router Models and Interfaces (continued)
Model
Ethernet
(10BASE-T)
Token-Ring
(RJ-45)
Fast
Ethernet
(10/100)
Network
Module Slot
WAN
Interface
Card Slots
Advanced
Integration
Module Slots