3Com 5500-SI Configuration Manual page 60

60 C 3: P O
HAPTER ORT PERATION
can configure to tag some VLAN packets, based on which the packets can be
processed differently.
Setting the Default VLAN ID for the Ethernet Port
Because the access port can only be included in one VLAN, its default VLAN is the one
to which it belongs. Because a hybrid port and a trunk port can be included in several
VLANs, you must configure the default VLAN ID. If the default VLAN ID has been
configured, the packets without VLAN Tag will be forwarded to the port that belongs
to the default VLAN. When sending the packets with VLAN Tag, if the VLAN ID of the
packet is identical to the default VLAN ID of the port, the system will remove VLAN
Tag before sending this packet.
Perform the following configuration in Ethernet Port View.
Table 43 Setting the Default VLAN ID for an Ethernet Port
Operation
Set the default VLAN ID for a hybrid port.
Set the default VLAN ID for a trunk port
Restore the default VLAN ID of a hybrid port to the
default value
Restore the default VLAN ID of a trunk port to the
default value
By default, the VLAN of a hybrid port and a trunk port is VLAN 1 and that of the
access port is the VLAN to which it belongs.
Note that to guarantee the proper packet transmission, the default VLAN ID of the
local hybrid port or trunk port should be identical with that of the hybrid port or trunk
port on the peer Switch.
Configuring Loopback Detection for Ethernet Ports
The goal of loopback detection is to check whether the ports of switch have
loopback.
After users enable loopback detection for Ethernet ports, the switch will monitor
whether the ports have loopback on a regular basis; if the switch detects loopback for
a particular port, it will put that port under control.
For Access port: If system detects loopback for a port, it will shut down that port,
■
send a Trap message to the terminal, and delete the corresponding MAC address
forwarding entry.
For Trunk ports and Hybrid ports: If system detects loopback for a port, it will send
■
a Trap message to the terminal. If the loopback detection and control function for
that port is enabled at the same time, the system will then shut down the given
port, send a Trap message to the terminal, and delete the corresponding MAC
address forwarding entry.
Table 44 Configure loopback detection for Ethernet port
Operation
Enter system view
Enable the global port
loopback detection
Set the time interval for
loopback detection function
Command
port hybrid pvid vlan
vlan_id
port trunk pvid vlan vlan_id
undo port hybrid pvid
undo port trunk pvid
Command Description
system-view -
loopback-detection Optional.By default, the global port
enable loopback detection function is disabled.
loopback-detection Optional.
interval-time time Set to 30 seconds by default.