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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 slot number for all WIC interfaces is always 0. (The W0 and W1 slot designations are for
physical slot identification only.) Interfaces in the WICs are numbered from right to left, starting with
0/0 for each interface type, regardless of which physical slot the WICs are installed in. Some
examples are:
–
If physical slot W0 is empty and physical slot W1 contains a 1-port serial WIC, the interface
number in the WIC is numbered Serial 0/0.
–
If slot W0 contains a 2-port serial WIC and slot W1 contains a 1-port serial WIC, the interfaces
in physical slot W0 are numbered Serial 0/0 and Serial 0/1, and the interface in physical slot W1
is numbered Serial 0/2.
–
If slot W0 contains a 2-port serial WIC and slot W1 contains a 1-port BRI WIC, the interfaces
in physical slot W0 are numbered Serial 0/0 and Serial 0/1, and the interface in physical slot W1
is numbered BRI 0/0.
Voice Interface Numbering in Cisco 2600 Series Routers
Voice interfaces are numbered differently from the WAN interfaces described in the previous section.
Voice interfaces are numbered as follows:
chassis slot/voice module slot/voice interface
If a 4-channel voice network module is installed in chassis slot 1, the voice interfaces are:
•
1/0/0—Chassis slot 1/Voice module slot 0/Voice interface 0
•
1/0/1—Chassis slot 1/Voice module slot 0/Voice interface 1
•
1/1/0—Chassis slot 1/Voice module slot 1/Voice interface 0
•
1/1/1—Chassis slot 1/Voice module slot 1/Voice interface 1
Cisco 3600 Series Interface Numbering
Each individual network interface on a Cisco 3600 series router is identified by a slot number and a unit
number.
Cisco 3600 Series Router Slot Numbering
A Cisco 3600 series router chassis includes up to six slots in which you can install modules. The
Cisco 3600 series includes the Cisco 3660 (see
Figure 1-3
), Cisco 3640 (see
Figure 1-4
) and Cisco 3620
routers (see
Figure 1-5
). The Cisco 3660 has six network module slots, the Cisco 3640 has four slots,
the Cisco 3620 has two slots, and the Cisco 3631 (see
Figure 1-6
) has four slots. You can install any
module into any available slot in the chassis.