3Com Router User Manual

Configure Bridge’s Routing Function297
will be routed through IP. Certainly, if IP cannot find a route, it will discard the 
packet instead of forwarding it to the bridge for processing. If the packet uses a 
protocol other than IP (for example, if it is the packet from the network like 
AppleTalk or DecNet), it will be bridged.
For the 3Com Router series, if the bridging function is not enabled, all the IP 
packets will be routed through IP. If it is enabled, the packets in the bridge-set will 
be...

298CHAPTER 19: CONFIGURING BRIDGE
2Configure Bridge-Set
Each bridge set is independent, and packets can not be transmitted between the 
ports belonging to different bridge sets. That is, the packets received via one 
bridge set port can only be sent via the ports of the same bridge set. One physical 
interface can only be added to one bridge set.
The bridges support several STP versions and these versions are not compatible. 
Sometimes, different STP versions may result in bridge looping.
The 3Com Router...

Configure Bridge’s Routing Function299
Perform the following configuration in system view.
Ta b l e 324   Enable/Disable forwarding by using dynamic address table
By default, the dynamic address table is used to forward frames.
cConfigure the aging time of dynamic address table
The aging time of dynamic address table refers to the time that an entry can 
remain in the address table before it is deleted. The aging time is controlled by 
the aging timer. Upon the expiration of the timer, the entry will be...

300CHAPTER 19: CONFIGURING BRIDGE
Ta b l e 327   Configure the bridge priority
By default, the bridge priority is 32768. It is valued in the range of 0 to 65535.
cConfigure the path cost of bridge port
The path cost of the port is related to its link speed. The higher the link speed 
is, the lower the path cost should be configured. 
If the port is configured with 
the default path cost, STP will automatically detect the current link speed of the 
port and accordingly compute the path cost on the port....

Configure Bridge’s Routing Function301
Ta b l e 330   Configure the interval for sending BPDUs
By default, the value of Hello Time timer is 2 seconds. It is in the range of 1 to 
10 seconds.
When configuring the Hello Time timer, it should be noted that:
■In the spanning tree, all the bridges use the time value of Hello Time timer 
of the root bridge, and their own configurations take no effect.
■Too long a Hello Time will cause the bridge to recompute the spanning tree 
because it considers the packet...

302CHAPTER 19: CONFIGURING BRIDGE
The Max Age is the parameter used to judge whether the BPDUs are 
“timeout”. Users can configure it according to the actual network conditions. 
When a port enables the STP, the Max Age timer begins to time. If no BPDU is 
received in the specified period, it will assume that the link has failed and the 
STP will recompute the minimum spanning tree.
Perform the following configuration in system view.
Ta b l e 332   Configure the Max age of BPDU
By default, the value of...

Configure Bridge’s Routing Function303
When creating an ACL based on Ethernet type code (Ethernet-II, SNAP or 
LSAP), you can specify aclt-number in the range of 200 to 299. type-code is a 
16-bit hexadecimal number written with a leading “0x”, corresponding to the 
type-code field in the Ethernet-II or SNAP frames. type-wildcard is a 16-bit 
hexadecimal number written with a leading “0x” and used to specify the 
shielded bits.
When creating an ACL, note that:
■The rules will be compared in the order in...

304CHAPTER 19: CONFIGURING BRIDGE
By default, no ACL is applied on the port.
When applying an ACL on the port, note that:
■Add the port to a bridge-set first, then apply the ACL on that port.
■If ACLs of the same type are applied to the same port, the latest ACL 
applied will replace the previous ones.
8Configure Routing Function
aEnable routing function
For the data of a specified protocol, they will be bridged if the communication 
is carried out between the bridge ports. If the communication with a...

Configure Bridge’s Routing Function305
Ta b l e 340   Configure bridge set to route or bridge the network layer protocol
By default, the bridging is enabled, the routing is disabled.
You can execute the display bridge bridge-set bridge-template 
command to view the configuration of routing and bridging on each interface.
9Configure Link-Set
aDefine a link-set
The link set can bundle multiple parallel links between two bridges, thus 
sharing loads among multiple links and enhancing link bandwidth...

306CHAPTER 19: CONFIGURING BRIDGE
Ta b l e 343   Map the bridge address to DLCI
11Configure Bridging over BDR
Perform the following configuration in system view.
aDefine a dialer list
Ta b l e 344   Define a dialer list
bConfigure the bridge interface
Perform the following configuration in interface view.
Ta b l e 345   Configuration on the interface
12Configure Bridging over LAPB
Perform the following configuration in interface view.
Ta b l e 346   Configure the link layer protocol of the interface to...