c2821 Maximum Number of Vlans encap. dot1q

Answered Question
Jan 15th, 2009
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How many Vlans encapsulation dot1q does support an c2821 with 2 Gigabit Ethernet interfaces?

Thanks.


Correct Answer by Giuseppe Larosa about 8 years 3 months ago

Hello Mariano,

in a router each Vlan subif takes a row in the IDB = interface descriptor block.


the total of physical and logical interfaces on your router cannot be higher then the IDB size.


This number is dependent on platform and IOS version.


on a c2821 the IDB can be 512

I didn't find the number so you should be able to implement several subinterfaces on your router.


2821


900


see


http://www.cisco.com/en/US/products/sw/iosswrel/ps1835/products_tech_note09186a0080094322.shtml#idb_limits


I shouldn't go behind 20 subinterfaces per GE there are other factors to be considered like the size of the NIC MAC packet filter.


Hope to help

Giuseppe




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Correct Answer
Giuseppe Larosa Thu, 01/15/2009 - 13:28
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Hello Mariano,

in a router each Vlan subif takes a row in the IDB = interface descriptor block.


the total of physical and logical interfaces on your router cannot be higher then the IDB size.


This number is dependent on platform and IOS version.


on a c2821 the IDB can be 512

I didn't find the number so you should be able to implement several subinterfaces on your router.


2821


900


see


http://www.cisco.com/en/US/products/sw/iosswrel/ps1835/products_tech_note09186a0080094322.shtml#idb_limits


I shouldn't go behind 20 subinterfaces per GE there are other factors to be considered like the size of the NIC MAC packet filter.


Hope to help

Giuseppe




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