1-10
Software Configuration Guide For Cisco 2600 Series, Cisco 3600 Series, and Cisco 3700 Series Routers
OL-1957-04
Chapter1 Understanding Interface Numbering and Cisco IOS Software Basics
Understanding Interface Numbering
• 1 for interfaces in the single-width network module slot
• 2 for interfaces in the double-width network module slot
Interface (port) numbers begin at 0 for each interface type, and continue from right to left and (if
necessary) from bottom to top.
Figure1-10 below shows an example of interface numbering on a Cisco 3725 router with:
• A WIC in each WIC slot (containing interfaces Serial 0/0 and Serial 0/1 in physical slot W0,
interface Serial 0/2 in physical slot W1, and interface BRI 0/0 in physical slot W2)
• A 2-port T1 network module in slot1 (containing the following ports: T1 1/0 and T1 1/1)
• A 36-port Etherswitch network module in slot2 (containing the following ports: FastEthernet 2/0
through 2/35, and GigabitEthernet 2/0 and 2/1)
• Two built-in Ethernet 10/100 interfaces—FastEthernet 0/0 and FastEthernet 0/1
Figure1-10 Cisco 3725 Router Rear View
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 in
the WIC is numbered Serial0/0.
–
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.
Cisco 3745 Router Interface Numbering
The Cisco 3745 router chassis contains the following wide-area network (WAN) and local-area network
(LAN) interface types:
• 2 built-in FastEthernet LAN interfaces
To Next Page
Loading...
Need help?
General
