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Re: [MEXT] [WGLC] draft-ietf-mext-flow-binding-03
On 26/10/09 10:11 PM, "Yuri Ismailov" <yuri.ismailov at ericsson.com> wrote:
> Hi Hesham,
>
> If, for example, there is a FID which covers range of port numbers and IP
> addresses. In such case flow bindings may look like as following
>
> FID-PRI FID Flow Description BIDs Action A/I
> ------- --- ---------------- ---- ------- ------
> 10 4 TCP dstPortMin=P1 1 Forward Active
> dstPortMax=PN
>
> If an MN whishes to discard some particular port number P1 < i < PN then the
> only possibility with the current FID table is to set
> The whole range to the state "Discard"
=> No, that's not a good way to go at all. If you want to do that the way to
say discard port 100 where P1 < 100 < N then you send a new FID with Discard
action, PRI set to say 9 (higher priority). You don't need to touch the
existing one.
Hesham
>
> If other port numbers in the range should be still in Active state then the
> new FID definitions will be required and flow bindings will have to be
> transformed looking like the following, for example:
>
> FID-PRI FID Flow Description BIDs Action A/I
> ------- --- ---------------- ---- ------- ------
> 10 4 TCP dstPortMin=P1 1 Forward Active
> dstPortMax=P(i-1)
>
> 10 5 TCP dstPortMin=P(i+1) 1 Forward Active
> dstPortMax=PN
>
> 10 6 TCP dstPortMin=i 1 Discard Active
>
> Similar should be done if there are ranges of IP addresses and/or both IP
> addresses and port numbers covered by a single FID
>
> Does this clarify what I mean?
>
> Regards
> Yuri
>
>
>
>
>
>
> -----Original Message-----
> From: Hesham Soliman [mailto:hesham at elevatemobile.com]
> Sent: Monday, October 26, 2009 9:59 AM
> To: Yuri Ismailov; George Tsirtsis
> Cc: Laganier, Julien; mext at ietf.org
> Subject: Re: [MEXT] [WGLC] draft-ietf-mext-flow-binding-03
>
> Yuri,
>
>
>>
>> After the text:
>>
>> "1 Discard. This value indicates a request to discard all packets in
>> the flow described by the option. No BIDs are associated with this
>> Action."
>>
>> Add the following text:
>>
>> "In the case there is no correspondent FID to a particular flow or
>> range of flows, which should be discarded, a mobile node MUST install
>> a correspondent FID, otherwise error code 136 "FID not found" will be
>> returned by HA.
>
> => I don't understand what this means. Can you clarify?
>
>
> Care
>> should be taken when issuing request for discarding packets as this
>> will lead to disrupting applications communication after the "Discard"
>> action was applied to selected flows. Implementations may consider
>> notifying impacted applications in mobile nodes"
>
> => This part is clear to me.
>
> Hesham
>
>>
>>
>>
>> Regards
>> Yuri
>>
>>
>> -----Original Message-----
>> From: George Tsirtsis [mailto:tsirtsis at googlemail.com]
>> Sent: Friday, October 23, 2009 5:54 PM
>> To: Yuri Ismailov
>> Cc: Laganier, Julien; mext at ietf.org
>> Subject: Re: [MEXT] [WGLC] draft-ietf-mext-flow-binding-03
>>
>> Hi Yuri, comments inline.
>>
>> On Fri, Oct 23, 2009 at 1:20 PM, Yuri Ismailov
>> <yuri.ismailov at ericsson.com>
>> wrote:
>>> Hi Goerge,
>>> Thanks for the answers,
>>> What I did not understand if there will be some clarification text in
>>> the draft around "discard" action or all that is obvious and does not
>>> require any changes? My comment was that some additional text is needed.
>>>
>>
>> GT> I am not yet sure what non-trivial clarification we can provide.
>> IMO we do not need to provide any further clarifications on this subject.
>>
>>> I do not think your clarification about using FID-PRI is quite clear.
>>> The reason is that there is no FID for a particular flow within the
>>> range There is only a FID for the whole range of port numbers and/or IP
>>> addresses.
>>>
>>
>> GT> What prevents you from creating another FID that is specific for
>> GT> that
>> flow?
>>
>>> Surprized that disclaimer for n-cast about carefull use is in the
>>> text and about disclaimer for "discard" you just say "I do not think
>>> there is anything to say here." Still the question is will there be related
>>> text?
>>>
>>
>> GT> I think the implication of dropping packets is much clearer than
>> the implication of n-casting. Dropping packets means the application
>> to which the packet is sent will not receive the packet...do we really
>> need to say that? On the other hand, receiving N copies of the same
>> packet has some implications to TCP....this is also rather obvious for
>> people that know TCP...but maybe not everyone does.
>>
>>> Regards
>>> Yuri
>>>
>>>
>>> -----Original Message-----
>>> From: George Tsirtsis [mailto:tsirtsis at googlemail.com]
>>> Sent: Friday, October 23, 2009 11:08 AM
>>> To: Yuri Ismailov
>>> Cc: Laganier, Julien; mext at ietf.org
>>> Subject: Re: [MEXT] [WGLC] draft-ietf-mext-flow-binding-03
>>>
>>> Hi Yuri,
>>>
>>> Comments inline...
>>>
>>> On Tue, Oct 20, 2009 at 8:55 AM, Yuri Ismailov
>>> <yuri.ismailov at ericsson.com>
>>> wrote:
>>>> Hi,
>>>> after re-reading the draft come up with the comment on "Discard"
>>>> action in "Flow Identification Mobility Option"
>>>> I suggest either to extend the paragraph in the section 4.2 or add a
>>>> separate subsection clarifying behavior of MN and HA before and
>>>> after the "Discard" action was issued by MN.
>>>>
>>>> Below are the issues which are proposed to be addressed in the text.
>>>>
>>>> 1.The case when installed FID represent ranges of port numbers and
>>>> IP addresses. If MN decides to discard a particular flow within the
>>>> range then before that a correspondent FID should be installed in the HA.
>>>> Otherwise
>>>> "136 FID not found" will be returned from HA.
>>>>
>>>
>>> GT> If the MN wants to discard a particular flow within a range of
>>> previously registered flows, it needs to either split the range it
>>> two parts, or even better, use a higher FID-PRI for the discard flow
>>> so that packets get matched against it before they get matched against the
>>> range.
>>>
>>>> 2. Specify the time interval for how long time the "Discard" state
>>>> will be active in HA. This is necessary because there is no
>>>> "un-discard" message sent from MN.
>>>>
>>>
>>> GT> Flow bindings share the same lifetime with the BU. There is no
>>> flow binding-specific lifetime. If an MN wants to remove a flow
>>> binding it sends a BU which does not include the corresponding FID.
>>>
>>>> 3. Add a disclaimer that for some protocols, like TCP, "Discard"
>>>> action may lead to hanging up the connection at CN and should be
>>>> used responsibly.
>>>>
>>>
>>> GT> Discarding packets will drop connections....yes...I do not think
>>> there is anything to say here.
>>>
>>>>
>>>> Regards
>>>> Yuri
>>>>
>>>>
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>>>>
>>>>
>>>
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