Abhay D.S.,
Sorry about the top post, but..
TCP has a slow-start mechanism with ACK
clocking to verify completion of xmit'ed data,
until a threshold is met or,
Until 2 or 3 DUP ACKs are seen and then
rexmited or a coarse grain timeout occurs,
However, TCP does not guarantee that the
recvr will actually recieve data xmited
by the send, just that if the data arrives
then, it will send acks..
And again, their is no guarantee that the
acks will be recieved, so the sender can
send more data.
Mitchell Erblich
-----------------
> "Abhay D.S" wrote:
>
> Hello Acee,
>
> a) Restart complete variable poll is one method after restart
>
> I am trying to find a method before restart to be deterministic.
>
> A simple analogy in TCP.
>
> For example..in TCP, just after connection establishment, I want
> start sending data, at the same time the remote link had some problem.
>
>
> a) Scenario 1
>
> 0sec .....5 Sec...(ok).....10 Sec (ok).....15 Sec (ok).....[DONE]
>
> Continue restart y/n ? : y
>
> Attempting graceful restart.....
>
> [OK]
>
> b) Scenario 2
>
> 0sec .....5 Sec...(ok).....10 Sec (Wait a While)....[Retrying due to
> network conditions]
>
>
> 0sec .....5 Sec...(Wait a While).....10 Sec (Ok)...15 Sec
> (ok).....[DONE]
>
> Continue restart y/n ? : y
>
> Attempting graceful restart......
>
> [OK]
>
> c) Scenario 3
>
> 0sec .....5 Sec...(ok).....10 Sec (Wait a While)....[Retrying due to
> network conditions]
>
>
> 0sec .....5 Sec...(Wait a While).....10 Sec (Ok)...15 Sec (Wait a
> While).....[Retrying due to network conditions]
>
> 0sec .....5 Sec...(ok).....10 Sec (Wait a While)....[Retrying due to
> network conditions]
>
> Continuing restart may affect forwarding...
> Continue anyway ? y/n .....n
>
> [OK]
>
>
> The time line above considers a network stable.
>
>
> After the restart is done I can follow method a)
>
>
> Thanks for your reply,
> Regards,
> Abhay
>
>
>
>
>
>
> ----- Original Message -----
> From: Acee Lindem
> To: Abhay D.S
> Cc: [email protected]
> Sent: Friday, October 19, 2007 9:13 PM
> Subject: Re: [OSPF] Cascaded Graceful Restarts with NSF for
> OSPF protocol Question
>
> Hi Abhay,
> Most of this borders on the implementation of the networking
> equipment's in-service upgrade. For now, let's just assume
> that you have redundant data place connectivity for the new
> line cards and solely need do the graceful restarts as
> indicated below. Again, this borders more on implementation.
> However, now the OSPFv2 MIB as described in RFC 4750 does
> support a variable which could be polled to determine when
> restart on a given router has completed.
>
> ospfRestartStatus OBJECT-TYPE
> SYNTAX INTEGER { notRestarting (1),
> plannedRestart (2),
> unplannedRestart (3)
> }
> MAX-ACCESS read-only
> STATUS current
> DESCRIPTION
> "Current status of OSPF graceful restart."
> ::= { ospfGeneralGroup 21 }
>
>
> Hope this helps,
> Acee
>
> On Oct 18, 2007, at 11:56 PM, Abhay D.S wrote:
>
> > hi all,
> >
> > Suppose I am providing real-time transactions over IP in a
> > non NSR environment(I dont invest much on getting a backup
> > RP i.e).
> >
> > But I have NSF, owing to the ease of which OSPF can be
> > used, I
> > use OSPF to manage connections to WAN.
> >
> > And I have bought new I/0 modules which require a restart
> > for
> > all my routers for proper installation.
> >
> > Luckily, I have inservice upgrade on the boxes.
> >
> > Assuming that I am a new operator without any
> > certifications under
> > my belt, I dont have a beautiful NMS with colored buttons.
> >
> > But I must implement the new I/O cards and its features
> > without disturbing
> > the users who are using the network for routing
> > transactions such as data
> > backup over network or voice forwarding and other
> > distributed applications
> > running over TCP/IP using my network.
> >
> > I want to graceful restart all my routers one by one,
> > called as cascaded
> > re-starts, how can I make sure the transition is done
> > seamlessly.
> >
> > I want the "this thing" to be automatic, since each router
> > is graceful
> > restarted
> > and then then the next one is re-started and then the next
> > one,
> > automatically.
> >
> > I can write a script to do that, but I am not sure the
> > forwarding will be
> > safe,
> > because it is difficult to control the network transient
> > conditions.
> >
> > Any mechanism available ?.
> >
> > Thanks and Regards,
> > Abhay
> >
> >
> >
> >
> > _______________________________________________
> > OSPF mailing list
> > [email protected]
> > https://www1.ietf.org/mailman/listinfo/ospf
> >
>
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