5-4
Catalyst 4500 Series, Catalyst 2948G, Catalyst 2948G-GE-TX, and Catalyst 2980G Switches Software Configuration Guide—Release 8.2GLX
78-15908-01
Chapter 5 Configuring Gigabit Ethernet Switching
Understanding How Gigabit Ethernet Works
Understanding How Oversubscribed Gigabit Ethernet Works
The Catalyst 4500 series Gigabit Ethernet modules provide a network-backbone connection for multiple
servers or high-end workstations. The following modules are supported:
•
WS-X4412-2GB-T
This 1000BASE-T 14-port module provides 2 dedicated uplink module ports (GBIC) and
12 oversubscribed ports (possible blocking).
•
WS-X4418-GB
This 1000BASE-X 18-port module provides 2 dedicated uplink module ports (GBIC) and
16 oversubscribed ports (possible blocking).
•
WS-X4424-GB-RJ45
This 10/100/100BASE-TX module provides 24 oversubscribed ports (possible blocking).
•
WS-X4448-GB-RJ24
This 10/100/100BASE-TX module provides 48 oversubscribed ports (possible blocking).
•
WS-X4448-LX
This Gigabit Ethernet optical line terminator module provides 48 oversubscribed ports (possible
blocking).
On all modules, each uplink module port has 1-Gbps dedicated bandwidth. These ports typically connect
to the network backbone.
Table 5-4
lists the uplink module port IDs for each module.
On all modules, the oversubscribed ports are segmented into groups of four ports each. Each group of
four ports shares 1 Gbps of bandwidth. The average bandwidth that clients and servers need to connect
to ports in the same group should not exceed 1 Gbps.
Table 5-5
shows how the oversubscribed ports are grouped for module WS-4412-2GB-TX.
Table 5-6
shows how the oversubscribed ports are grouped for module WS-4418-2GB.
Table 5-7
shows how the oversubscribed ports are grouped for module WS-X4424-GB-RJ45.
Table 5-4
Uplink Port Module IDs for Gigabit Ethernet Modules
Module
Port ID
WS-X4412-2GB-T
13 14
WS-X4418-GB
1 2
Table 5-5
Oversubscribed Port Groupings for Module WS-4412-2GB-TX
1, 2, 3, 4
5, 6, 7, 8
9, 10, 11, 12
Uplink Ports
(13, 14)
Table 5-6
Oversubscribed Port Groupings for Module WS-4418-2GB
Uplink Port 1
Uplink Port 2
3, 5, 7, 9
4, 6, 8, 10
11, 13, 15, 17
12, 14, 16, 18