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Pruning ISL trunks question

Can you guys confirm this for me please ?

1. If I prune a vlan from an isl trunk when the end switch has no member ports, I will save isl encapsulated broadcast traffic from going across the trunk for this vlan ?

2. If I convert my trunks from isl to 802.1q I will save 26 bytes for each frame. Perhaps more because with 802.1q I could have a native non encapsulated vlan and save even more ?

Is this good practice ?

Thanks

1 ACCEPTED SOLUTION

Accepted Solutions

Re: Pruning ISL trunks question

Hi Friend,

1. Yes

2. ISL encapsulation does not have a concept of Native vlan so yes native vlan on dot1q trunk will not have any tagging and yes if you configure dot1q you will save a header of 26 bytes but dot1q also puts a internal tagging of 4 bytes.

Yes it is definetely a good practice because first dot1q is open standard and second farme size get reduced.

HTH, if yes please rate the post.

Ankur

1 REPLY

Re: Pruning ISL trunks question

Hi Friend,

1. Yes

2. ISL encapsulation does not have a concept of Native vlan so yes native vlan on dot1q trunk will not have any tagging and yes if you configure dot1q you will save a header of 26 bytes but dot1q also puts a internal tagging of 4 bytes.

Yes it is definetely a good practice because first dot1q is open standard and second farme size get reduced.

HTH, if yes please rate the post.

Ankur

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