Operating instructions

102 Cisco Systems Intelligent Gigabit Ethernet Switch Module
the port on the Cisco Systems IGESM to be an access port (switchport mode access)
and then set the access VLAN to the desired VLAN (switchport access vlan x). You can
also change the default VLAN by leaving it trunked and changing the native VLAN to some
other value.
򐂰 Portfast and BPDU Filter enabled by default on blade server ports. Portfast and BPDU
filters can be disabled by users.
򐂰 All blade server ports are given a default description to match their function.
Ports G0/15 through G0/16: Connects to Management Modules 1 and 2, respectively:
򐂰 Preset default values for ports going to the Management Modules (includes ports g0/15
and g0/16, shown is for g0/15):
description mgmt1
switchport trunk allowed vlan 1
switchport mode trunk
switchport nonegotiate
spanning-tree cost 100
򐂰 Speed is hard-coded at 100 full and cannot be changed.
򐂰 Ports cannot be administratively shut down.
– This is by design to ensure that the links to the BladeCenter Management Modules are
not inadvertently brought down by the administrator.
– Note that only one of these ports (g0/15 or g0/16) will be active at one time (only one
Management Module is active at any given time). In most cases, port 15 going to
Management Module 1 is the active port, while port 16 will show as:
GigabitEthernet0/16 is down, line protocol is down (notconnect)
򐂰 This status for g0/16 will only change to up/up when the Cisco Systems IGESM receives
an event notification that the second Management Module is active.
򐂰 Both ports hard-coded as trunks and cannot be set to access ports.
򐂰 The management VLAN (default is VLAN 1) is always in a Spanning Tree forwarding state
on ports g0/15 and g0/16. This is to help ensure communications between the Cisco
Systems IGESMs and the Management Modules. All other VLANs can be put into the
blocking state through STP if a loop is detected.
Note that there is a hidden filter (not visible or controllable by the administrator) that
prevents any packet entering one of the uplink ports (g0/17 -20) from exiting toward the
Management Module ports (g0/5-16) and vise-versa. This ensures that packets will not
loop endless (prevents spanning tree loop).
Spanning Tree port cost is set to 100 by default (only effects non-management VLANs as
previously noted). This value can be changed by the user, but it is not recommended to do
so, because unexpected STP blocks might occur.
򐂰 VLAN characteristics for ports g0/15 and g0/16 can only be changed by changing the
management VLAN.
When activating a different management VLAN (for example, create a new VLAN, create a
new VLAN interface, and then do a no shut). Ports g0/15 and g0/16 will automatically
make this VLAN their native VLAN and allow it to pass on their trunked links (switchport
trunk allowed vlan X). This is by design and is the only way you can control the native
VLAN settings for these two ports.