Hi Acee,
I would like to thank you for finding time to reply my mail.
I had gone through section 10.6 and 10.8 still i would like to know in
section 10.6 what these below line means.
* The slave must send a Database Description Packet in reply.
If the received packet has the more bit (M) set to 0, and
the packet to be sent by the slave will also have the M-bit
**set to 0, the neighbor event ExchangeDone is generated.*
*Best Regards,*
*Biswajit Sadhu*
On Wed, Jul 3, 2013 at 7:00 PM, Acee Lindem <[email protected]>wrote:
> Hi Biswajit,
>
> On Jul 3, 2013, at 6:35 AM, Biswajit Sadhu wrote:
>
> Hi All,
>
> I have a query in the OSPF Design of LSA Data Base Exchange.
>
> In data base exchange process if the master has smaller database the the
> slave and the master sends the More bit as zero in its DB packet then the
> slave should also set the M bit to 0 in reply to the master's DB packet
> with the same sequence number ?
>
>
> No. The slave should continue to set the M bit until it has sent its
> entire database. The master should continue to poll the slave with
> increasing sequence numbers until the slave has completed exchanging its
> entire database and cleared the M bit. Excerpt from RFC 2328:
>
> This sending and receiving of Database Description packets is
> called the "Database Exchange Process". During this process,
> the two routers form a master/slave relationship. Each Database
> Description Packet has a sequence number. Database Description
> Packets sent by the master (polls) are acknowledged by the slave
> through echoing of the sequence number. Both polls and their
> responses contain summaries of link state data. The master is
> the only one allowed to retransmit Database Description Packets.
> It does so only at fixed intervals, the length of which is the
> configured per-interface constant RxmtInterval.
>
> Each Database Description contains an indication that there are
> more packets to follow --- the M-bit. The Database Exchange
> Process is over when a router has received and sent Database
> Description Packets with the M-bit off.
>
> Read RFC 2328 sections 10.6 and 10.8 and it should be clear. The actions of
> the database exchange master and slave are described in detail.
>
>
> Hope this Helps,
> Acee
>
>
>
>
>
>
>
>
> Should the data base exchange stop after that. what if the slave had
> more lsa's to send to the Master?
>
> What about the vice-versa case where Master has a large Data base to
> exchange then the Slave ?
>
> As per page 101 .rfc 2328 i am quoting few lines for the same RFC
>
> http://tools.ietf.org/html/rfc2328
>
>
> * Master
> Increments the DD sequence number in the neighbor data
> structure. If the router has already sent its entire
> sequence of Database Description Packets, and the just
> accepted packet has the more bit (M) set to 0, the neighbor
> event ExchangeDone is generated. Otherwise, it should send
> a new Database Description to the slave.
>
> Slave
> Sets the DD sequence number in the neighbor data structure
> to the DD sequence number appearing in the received packet.
> The slave must send a Database Description Packet in reply.
> If the received packet has the more bit (M) set to 0, and
> the packet to be sent by the slave will also have the M-bit
> **set to 0, the neighbor event ExchangeDone is generated.**
> Note that the slave always generates this event before the
> maste**r.*
>
> *
> *
>
> *Best Regards,*
>
> *Biswajit Sadhu*
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>
>
>
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