Dual-Purpose Uplink Ports; Connecting Interfaces - Cisco WS-C3020 Software Configuration Manual

Understanding Interface Types

Dual-Purpose Uplink Ports

The Cisco Catalyst Blade Switch 3020 for HP supports dual-purpose uplink ports on six of the eight
uplink ports. Four of the uplink ports, 17 to 20, are considered as a single interface with dual front ends
(an RJ-45 connector and an SFP module connector). The dual front ends on ports 17 to 20 are not
redundant interfaces, and the switch activates only one connector of the pair.
By default, the switch dynamically selects the interface type that first links up. However, you can use the
media-type interface configuration command to manually select the RJ-45 connector or the SFP module
connector. For information about configuring speed and duplex settings for a dual-purpose uplink, see
the
Uplink ports 17 to 20 have two LEDs: one shows the status of the RJ-45 port, and one shows the status
of the SFP module port. The port LED is on for whichever connector is active. For more information
about the LEDs, see the hardware installation guide.
Ports 23x and 24x are different from the other dual-purpose ports. When operating in external mode,
these ports are single, uplink 10/100/1000BASE-T copper Gigabit Ethernet ports. When operating in
internal mode, they use the 1000BASE-X mode, and they form a cross-connection with a switch that is
installed in a corresponding module bay in the blade server. The default operation mode for ports 23x
and 24x is external, set by using the rj45 keyword of the media-type interface configuration command.

Connecting Interfaces

Devices within a single VLAN can communicate directly through any switch. Ports in different VLANs
cannot exchange data without going through a routing device. In the configuration shown in
when Blade Server A in VLAN 20 sends data to Blade Server B in VLAN 30, the data must go from
Blade Server A to the switch, to the router, back to the switch, and then to Blade Server B.
Figure 9-1
Server A
By using the switch with routing enabled, when you configure both VLAN 20 and VLAN 30 with an
SVI to which an IP address is assigned, packets can be sent from Host A to Host B directly through the
switch with no need for an external router.
Cisco Catalyst Blade Switch 3020 for HP Software Configuration Guide
9-6
"Setting the Interface Speed and Duplex Parameters" section on page
Connecting VLANs with Layer 2 Switches
Blade
VLAN 20
Chapter 9
Cisco router
Blade Switch
Blade
Server B
VLAN 30
Configuring Interface Characteristics
9-16.
Figure
OL-8915-03
9-1,