Subject: [mpls] Re: ping for static LSPs?

From: "Adrian Farrel" <[email-masked]>
Date: Wed, 3 Oct 2007 11:28:08 +0100

Shilpa,

Since no-one else answered, I'll bite.

>  I have a query regarding ping support for static LSPs.
>
> Firstly, is it supported?

I don't believe that there is anything in the definition of LSP Ping that 
makes the use of a control plane to establish the LSP mandatory.

> Secondly, if Control Plane is implementing LSR MIB (which does not hold 
> any
> information about FECs) to use for setting up of static LSPs, then when an
> echo request packet (with FEC TLV) is received by Data Plane, then how can
> one verify DP against CP?

I don't think the control plane implements the LSR MIB. That would be "the 
LSR". But, anyway...

The deeper question you are asking is: how is the FEC-To-NHLFE table built 
at an LSR through management plane activity?

You are correct that the LSR MIB module (RFC3813) only defines how to set up 
the LFIB.
You should look at RFC3814 to see how the FEC-To-NHLFE table can be built 
using a MIB module.

You may want to look at RFC4221 to see an overview of how all of the MPLS 
MIB modules fit together.

Cheers,
Adrian 

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---

From: shilpa goel <[email-masked]>
Date: Wed, 03 Oct 2007 16:36:53 +0530

---------- Forwarded message ----------
From: shilpa goel <[email-masked]>
Date: Oct 3, 2007 4:20 PM
Subject: Re: ping for static LSPs?
To: Adrian Farrel <[email-masked]>

Adrian,

  What I meant was that suppose MPLS DP is implementing FTN MIB while MPLS
CP is implementing LSR MIB. In this scenario, when a static LSP is set up,
LSR MIB is configured in the CP with the cross-connect/LSP. This cross
connect information is passed to DP. FTN MIB is then configured in DP with
an FEC to this cross-connect/LSP mapping.

Now consider such a LSP is pinged. When it reached the egress node, it is
required that DP passes this packet to CP for "Egress FEC validation"
(section 4.4, point 6 of RFC 4379). My doubt was that how can CP verify this
ping packet when it does not have any such "FEC" information in its LSR MIB
for this cross-connect/LSP.

thanks and regards,
Shilpa

---

From: "shilpa goel" <[email-masked]>
Date: Wed, 3 Oct 2007 16:36:53 +0530

---------- Forwarded message ----------
From: shilpa goel <[email-masked]>
Date: Oct 3, 2007 4:20 PM
Subject: Re: ping for static LSPs?
To: Adrian Farrel <[email-masked]>

Adrian,

thanks and regards,
Shilpa

---

From: Thomas D.Nadeau <[email-masked]>
Date: Wed, 3 Oct 2007 07:42:04 -0400

> I don't believe that there is anything in the definition of LSP  
> Ping that makes the use of a control plane to establish the LSP  
> mandatory.

	This is correct. LSP ping needs a target FEC, but doesn't care how  
that FEC to NHLFE mapping
was established whether though a signaling protocol or statically.

>> Secondly, if Control Plane is implementing LSR MIB (which does not  
>> hold any
> I don't think the control plane implements the LSR MIB. That would  
> be "the LSR". But, anyway...

	The LSR-MIB is implemented in the control plane, but I think the  
original poster is confused about
its use if you are using it to validate echo reply packets; that is  
not its purpose.

> The deeper question you are asking is: how is the FEC-To-NHLFE  
> table built at an LSR through management plane activity?
>
> You are correct that the LSR MIB module (RFC3813) only defines how  
> to set up the LFIB.
> You should look at RFC3814 to see how the FEC-To-NHLFE table can be  
> built using a MIB module.
>
> You may want to From [email-masked] Wed Oct 03 07:43:02 2007
From: Thomas D.Nadeau <[email-masked]>
Subject: Re: [mpls] Re: ping for static LSPs?
Date: Wed, 3 Oct 2007 07:42:04 -0400
To: Adrian Farrel <[email-masked]>
Cc: [email-masked], shilpa goel <[email-masked]>, [email-masked]

> I don't believe that there is anything in the definition of LSP  
> Ping that makes the use of a control plane to establish the LSP  
> mandatory.

	This is correct. LSP ping needs a target FEC, but doesn't care how  
that FEC to NHLFE mapping
was established whether though a signaling protocol or statically.

>> Secondly, if Control Plane is implementing LSR MIB (which does not  
>> hold any
> I don't think the control plane implements the LSR MIB. That would  
> be "the LSR". But, anyway...

	The LSR-MIB is implemented in the control plane, but I think the  
original poster is confused about
its use if you are using it to validate echo reply packets; that is  
not its purpose.

> The deeper question you are asking is: how is the FEC-To-NHLFE  
> table built at an LSR through management plane activity?
>
> You are correct that the LSR MIB module (RFC3813) only defines how  
> to set up the LFIB.
> You should look at RFC3814 to see how the FEC-To-NHLFE table can be  
> built using a MIB module.
>
> You may want to look at RFC4221 to see an overview of how all of  
> the MPLS MIB modules fit together.

	Agreed, although I will also point out that it appears the original  
poster needs a clearer
understanding of what the control and data planes do before  
implementing LSP ping too,
which may or may not come from reading the original MPLS RFCs such as  
RFC3031.

	--Tom

---

From: "Thomas D. Nadeau" <[email-masked]>
Date: Wed, 3 Oct 2007 07:36:07 -0400

>> echo request packet (with FEC TLV) is received by Data Plane, then  
>> how calook at RFC4221 to see an overview of how all of  

	--Tom

---

From: "Thomas D. Nadeau" <[email-masked]>
Date: Wed, 3 Oct 2007 07:36:07 -0400

>> how can

	--Tom

n

	--Tom

---

From: "Thomas D. Nadeau" <[email-masked]>
Date: Wed, 3 Oct 2007 07:39:40 -0400

On Oct 3, 2007, at 7:06 AM, shilpa goel wrote:

>   What I meant was that suppose MPLS DP is implementing FTN MIB  
> while MPLS CP is implementing LSR MIB. In this scenario, when a  
> static LSP is set up, LSR MIB is configured in the CP with the  
> cross-connect/LSP. This cross connect information is passed to DP.  
> FTN MIB is then configured in DP with an FEC to this cross-connect/ 
> LSP mapping.

	Again, I think you are a bit confused about how the MIBs are used.  
The XCEntry is a "mib only thing"
used to bind together the incoming and outgoing labels. Internally,  
this can actually be a variety of
things, but suffice to say it has really nothing to do with lsp ping  
except that when validating an echo
request, you are consulting the same control plane information under  
the covers.   You are also
validating that the data plane is consistent with this view of the  
world as well.

> Now consider such a LSP is pinged.
> When it reached the egress node, it is required that DP passes this  
> packet to CP for "Egress FEC validation" (section 4.4, point 6 of  
> RFC 4379). My doubt was that how can CP verify this ping packet  
> when it does not have any such "FEC" information in its LSR MIB for  
> this cross-connect/LSP.

	The target FEC information is included in the echo request message.  
It should be compared against
that of the receiving LSR to determine among other things, if this  
packet was indeed destined
for the LSR on which it is terminating.

	--Tom

>
>
> thanks and regards,
> Shilpa
>
>
> On 10/3/07, Adrian Farrel < [email-masked]> wrote:
> Shilpa,
>
> Ping that
> table built
> to set up
> built

---

From: Thomas D.Nadeau <[email-masked]>
Date: Wed, 3 Oct 2007 07:42:11 -0400

--Tom

---

From: "Adrian Farrel" <[email-masked]>
Date: Wed, 3 Oct 2007 12:58:28 +0100

Hi,

> an FEC to this cross-connect/LSP mapping.

Well, first, you must get off this thing about the CP or DP implementing a
MIB.
The LSR is one big, happy family.
The MIB is present in the management plane. The information that is stored
to correspond to the MIB objects may be stored in the CP or DP.

When Tom says that he thinks the LSR MIB is implemented in the control 
plane, I tend to disagree. It is perfectly possible to have no control plane 
on an LSR and still have access to the LFIB information through the LSR MIB. 
(Of course, how LSRs are actually built is a different matter.)

> (section 4.4, point 6 of RFC 4379).

Why is the Ping packet passed to the CP?
Because LSP Ping is a CP protocol.
Thus, the module that processes the packet is a CP module.

> My doubt was that how can CP verify this
> ping packet when it does not have any such "FEC"
> information in its LSR MIB for this cross-connect/LSP.

If your CP implementation is unable to read the FTN information stored in
the data plane then:
- you can't process the ping
- your implementation is probably badly broken!

At the very least (although this would be an incredibly bad idea) the CP
should be able to read the FTN MIB using SNMP.

Adrian

---

From: "David Allan" <[email-masked]>
Date: Wed, 3 Oct 2007 12:55:55 -0400

Just a thought but when doing a traceroute, the FTN information would
not be available in any form at transit nodes...?

C'est vrai?

Dave 

-----Original Message-----
From: Thomas D.Nadeau [mailto:[email-masked]] 
Sent: Wednesday, October 03, 2007 7:42 AM
To: Adrian Farrel
Cc: [email-masked]; shilpa goel; [email-masked]
Subject: Re: [mpls] Re: ping for static LSPs?

> I don't believe that there is anything in the definition of LSP Ping 
> that makes the use of a control plane to establish the LSP mandatory.

	This is correct. LSP ping needs a target FEC, but doesn't care
how that FEC to NHLFE mapping was established whether though a signaling
protocol or statically.

>> hold any information about FECs) to use for setting up of static 
>> LSPs, then when an echo request packet (with FEC TLV) is received by 
>> Data Plane, then how can one verify DP against CP?
>
> I don't think the control plane implements the LSR MIB. That would be 
> "the LSR". But, anyway...

	The LSR-MIB is implemented in the control plane, but I think the
original poster is confused about its use if you are using it to
validate echo reply packets; that is not its purpose.

> The deeper question you are asking is: how is the FEC-To-NHLFE table 
> built at an LSR through management plane activity?
>
> You are correct that the LSR MIB module (RFC3813) only defines how to 
> set up the LFIB.
> You may want to look at RFC4221 to see an overview of how all of the 
> MPLS MIB modules fit together.

	Agreed, although I will also point out that it appears the
original poster needs a clearer understanding of what the control and
data planes do before implementing LSP ping too, which may or may not
come from reading the original MPLS RFCs such as RFC3031.

	--Tom

---

From: lostcode <[email-masked]>
Date: Thu, 4 Oct 2007 22:47:50 +0800

lsp ping or lsp traceroute does not care about the information of CP.
 
After the lsp created, static lsp or else , the CP download the forwarding
information to DP, so a question occur, as the same fec, which one we should 
use ,the static lsp or signal lsp?

> Subject: RE: [mpls] Re: ping for static LSPs?> Date: Wed, 3 Oct 2007 12:55:55 -0400> From: [email-masked]> To: [email-masked]; [email-masked]> CC: [email-masked]; [email-masked]; [email-masked]> > Just a thought but when doing a traceroute, the FTN information would> not be available in any form at transit nodes...?> > C'est vrai?> > Dave > > -----Original Message-----> From: Thomas D.Nadeau [mailto:[email-masked]] > Sent: Wednesday, October 03, 2007 7:42 AM> To: Adrian Farrel> Cc: [email-masked]; shilpa goel; [email-masked]> Subject: Re: [mpls] Re: ping for static LSPs?> > > > > Shilpa,> >> > Since no-one else answered, I'll bite.> >> >> I have a query regarding ping support for static LSPs.> >>> >> Firstly, is it supported?> >> > I don't believe that there is anything in the definition of LSP Ping > > that makes the use of a control plane to establish the LSP mandatory.> > This is correct. LSP ping needs a target FEC, but doesn't care> how that FEC to NHLFE mapping was established whether though a signaling> protocol or statically.> > >> Secondly, if Control Plane is implementing LSR MIB (which does not > >> hold any information about FECs) to use for setting up of static > >> LSPs, then when an echo request packet (with FEC TLV) is received by > >> Data Plane, then how can one verify DP against CP?> >> > I don't think the control plane implements the LSR MIB. That would be > > "the LSR". But, anyway...> > The LSR-MIB is implemented in the control plane, but I think the> original poster is confused about its use if you are using it to> validate echo reply packets; that is not its purpose.> > > The deeper question you are asking is: how is the FEC-To-NHLFE table > > built at an LSR through management plane activity?> >> > You are correct that the LSR MIB module (RFC3813) only defines how to > > set up the LFIB.> > You should look at RFC3814 to see how the FEC-To-NHLFE table can be > > built using a MIB module.> >> > You may want to look at RFC4221 to see an overview of how all of the > > MPLS MIB modules fit together.> > Agreed, although I will also point out that it appears the> original poster needs a clearer understanding of what the control and> data planes do before implementing LSP ping too, which may or may not> come from reading the original MPLS RFCs such as RFC3031.> > --Tom> > > >> > Cheers,> > Adrian> >> >> >> > _______________________________________________> > mpls mailing list> > [email-masked]> > https://www1.ietf.org/mailman/listinfo/mpls> >> > > > _______________________________________________> mpls mailing list> [email-masked]> https://www1.ietf.org/mailman/listinfo/mpls> > > _______________________________________________> mpls mailing list> [email-masked]> https://www1.ietf.org/mailman/listinfo/mpls
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---

From: "Adrian Farrel" <[email-masked]>
Date: Wed, 3 Oct 2007 12:58:28 +0100

Hi,

Adrian 

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