Allied Telesis at-8700xl series switch manual IP Switching

Switching 69

The spanning tree algorithm ensures that the extended LAN contains no loops and that all LANs are connected by:

■Detecting the presence of loops and automatically computing a logical loop-free portion of the topology, called a spanning tree. The topology is dynamically pruned to a spanning tree by declaring the ports on a switch redundant, and placing the ports into a ‘Blocking’ state.

■Automatically recovering from a switch failure that would partition the extended LAN by reconfiguring the spanning tree to use redundant paths, if available.

Spanning Tree and Rapid Spanning Tree Port States

If STP is running in STANDARD mode, then each port can be in one of five Spanning Tree states, and one of two switch states. If STP is running in RAPID mode, then each port can be in one of four states. The state of a switch port is taken into account by STP. To be involved in STP negotiations, STP must be enabled on the switch, the port must be enabled on the switch, and enabled for the STP it belongs to.

IP Switching

The switch performs IP routing at wire speed between VLANs that have been configured as IP interfaces. For example, to add the admin VLAN as an IP interface, giving it an IP address of 192.168.163.39 in the subnet 192.168.163.0, first enable IP using the command:

ENABLE IP

Then use either of the following commands:

ADD IP INTERFACE=vlan-admin IPADDRESS=192.168.163.39

MASK=255.255.255.0

ADD IP INTERFACE=vlan11 IPADDRESS=192.168.163.39

MASK=255.255.255.0

The command:

SHOW IP INTERFACE

displays the interfaces enabled for IP routing (Figure 12).

For detailed information about configuring IP, see the Internet Protocol (IP) chapter in the AT-8700XL Series Software Reference.

Figure 12: Example output from the SHOW IP INTERFACE command.

Interface	Type	IP Address	Bc Fr PArp	Filt	RIP Met.	SAMode	IPSc
Pri. Filt	Pol.Filt	Network Mask	MTU VJC	GRE	OSPF Met.	DBcast	Mul.

--------------------------------------------------------------------------------

LOCAL	-	Not Set	-	n	-	---	-	-	--
---	----	-	-		-	---	-	-	---
vlan11	Static	192.168.163.39	1	y	On	---	01	Pass	--
---	---	255.255.255.0	1500		-	---	0000000001	No	On

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Software Release 2.6.1 C613-02030-00 REV B