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Re: [Lsr] Enhancement related to Area Leader Sub-TLV

Huaimo Chen <hchen@futurewei.com> Wed, 29 May 2019 05:13 UTC

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From: Huaimo Chen <hchen@futurewei.com>
To: "tony.li@tony.li" <tony.li@tony.li>
CC: "lsr@ietf.org" <lsr@ietf.org>
Thread-Topic: Enhancement related to Area Leader Sub-TLV
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Date: Wed, 29 May 2019 05:12:59 +0000
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Subject: Re: [Lsr] Enhancement related to Area Leader Sub-TLV
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Hi Tony,


    After moving, it seems OK for only the leader advertises a (Updated) Area Leader Sub-TLV. After the old/current leader dies, a new leader will be elected and the new leader will advertises a (Updated) Area Leader Sub-TLV.


    Since the other nodes do not advertise any Area Leader Sub-TLVs, the space used for advertising Area Leader Sub-TLVs by these nodes before moving should be saved.


Best Regards,

Huaimo

________________________________
From: Tony Li <tony1athome@gmail.com> on behalf of tony.li@tony.li <tony.li@tony.li>
Sent: Tuesday, May 28, 2019 11:20 AM
To: Huaimo Chen
Cc: lsr@ietf.org
Subject: Re: Enhancement related to Area Leader Sub-TLV


Hi Huaimo,


    Before moving, each of N nodes may advertise an Area Leader Sub-TLV and a Dynamic Flooding Sub-TLV. After moving, only the leader node advertises a (Updated) Area Leader Sub-TLV.


The Area Leader sub-TLV should be advertised by all nodes that are candidates to being Area Leader.  Strictly speaking, you could choose only one, but that would become a single point of failure.  For simple redundancy, two seems a practical minimum, however it still seems somewhat risky due to the possible loss of an Area Leader after a multi-failure partition. Thus, it is likely that all N nodes will continue to advertise the Area Leader sub-TLV.

Since no sub-TLVs are withdrawn, there is no space savings.

Tony

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