Re: RSVP and LDP

You can definately do this ..

There are 4 categories here

1) Tunnel from PE to PE
2) Tunnel from PE to P
3) Tunnel from P to PE
4) Tunnel from P to P

Options that you have mentioned needs special care in ensuring that labels
are not popped one hop too soon .

Hence on head end you say :

int tunnel 0
mpls ip

and on tail end you instruct the end to accept the targetted-hellos .

For more info you can just google around but this was just an overview
.There will be 3 label stack in this case .

Regards
Gaurav Madan
CCIE

2012/2/2 Mustafa Yadav <mustafa.yadav_at_gmail.com>

> This makes sense and. I have found ldp over rsvp is used and there are
> 3 labels are used.vpn rsvp and ldp label
>
> 2012/2/2, CCIE KID <eliteccie_at_gmail.com>:
> > Good explanation Hemanth
> >
> > TE is used to engineer the traffic as u want to go through with the
> > prioritized traffic in need of B.W. There many be different LSP's and
> you
> > assign different treatment for each LSP.
> > And also u can do LDP over RSVP where u can do RSVP TE Tunnel from one P
> to
> > another P . So from PE to P u run LDP and have a targeted LDP over ur
> RSVP
> > So its basically hierarchical LDP over ur RSVP .
> >
> > On Thu, Feb 2, 2012 at 6:13 PM, HEMANTH RAJ <hemanthrj_at_gmail.com> wrote:
> >
> >> Hi Mustafa
> >>
> >> LDP has been designed for distributing labels exclusively, But RSVP has
> >> been a Host based protocol to inform the transit routers that to reserve
> >> the bandwidth what the application needs.
> >> So here in MPLS TE , RSVP is used as a signalling protocol to establish
> a
> >> BANDWIDTH DEFINED LSP from head end router to your Tail End Router
> >>
> >> In ur normal LDP , For each prefix u build a particular LSP . These
> >> prefixes are distributed by ur CORE IGP. SO basically ur LDP is relying
> on
> >> ur IGP info for setting up a LSP for that prefix
> >>
> >> But in MPLS TE, RSVP will build a LSP with the Tail End Router with some
> >> constraints. So basically it is a Tunnel where ur Head End Router is
> >> trying
> >> to form with the Tail End and to switch packets on the Tunnel. It is a
> >> unidirectional Tunnel.
> >>
> >> TE also uses ur CORE IGP to check whether the requirements to form a
> >> tunnel are met. For example , If the TE Tunnel requires 500Kb of
> bandwidth
> >> ie ur Head End's routers requirement is 500Kbs of B.W end to end (
> Assume
> >> that there are some users sitting behind Head End Router which requires
> a
> >> 500kb feed from the server which is present behind ur Tail End Router )
> So
> >> now ur Head End has to know the end to end B.W capacity of each transit
> >> router . This information is fed by our CORE IGP which can be ISIS or
> OSPF
> >> . ( These r the two protocol in use currently which has the capability
> to
> >> carry MPLS TE extended attributes . OSPF uses Opaque LSA and ISIS uses
> >> extended TLVS for it )
> >>
> >> So TE Tunnel will be up only when it is met with these requirements and
> >> after that it signals the RSVP Path and Tail End will send Reserve
> >> Messages
> >> to assign Labels ..
> >> This is also same as ur LDP where ur Downstream router starts assigning
> >> labels to the prefixes.
> >>
> >> So basically LDP is a prefix driven label assignment protocol but RSVP
> is
> >> all about how ur Head End wants the Constraint driven LSP with ur Tail
> >> End
> >> router and ( so u must know ur network and u know there is greedy hosts
> >> which wants a feed and u configure the TE Tunnel accordingly )
> >>
> >> Without LDP also, RSVP will work .For RSVP u just need ur CORE IGP to be
> >> converged and has the capabilities to carry TE extended information ( So
> >> no
> >> RIP and EIGRP as of now ) RSVP Head End just sends Path message to ur
> >> Tail
> >> End router to signal each and every transit router that this is the
> >> requirement
> >>
> >> Do not confuse between LDP and RSVP. LDP is always Prefix Driven From
> IGP
> >> .. RSVP is basically manually configured Constraint Driven LSP ( knowing
> >> ur
> >> network end to end )
> >>
> >> Hope this helps :)
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >> On Thu, Feb 2, 2012 at 5:43 PM, GAURAV MADAN <gauravmadan1177_at_gmail.com
> >> >wrote:
> >>
> >> > I think things are being mixed up here .
> >> >
> >> > When RSVP is used with TE .. RSVP will do the label distribution .
> >> > Hence role of LDP as a protocol for label distibution is eliminated as
> >> you
> >> > are doing same thing using RSVP .
> >> >
> >> > And also ; i believe that in MPLS L3 VPN scenario as well ; running
> only
> >> > RSVP and no LDP anywhere in core can achieve your goal .
> >> >
> >> > Regards
> >> > Gaurav Madan
> >> > CCIE
> >> >
> >> > On Thu, Feb 2, 2012 at 5:14 PM, Mustafa Yadav <
> mustafa.yadav_at_gmail.com
> >> > >wrote:
> >> >
> >> > > so when ldp is going down all te tunnles are going to be down?
> >> > >
> >> > > but in one of my case ldp goes down but te tunnels did not.
> >> > >
> >> > > Also I seee ldp neigbor is up for 4 hours but mpls te tunnel up for
> 8
> >> > > hours.and 4 hours ago ldp went down.
> >> > >
> >> > > On Thu, Feb 2, 2012 at 1:18 PM, sundeep sadhwani <
> >> > > sundeep.sadhwani_at_gmail.com
> >> > > > wrote:
> >> > >
> >> > > > Hi Mustafa,
> >> > > >
> >> > > > RSVP is used for reservation of bandwidth in TE environment( i am
> >> > giving
> >> > > u
> >> > > > a very high level view). However plain MPLS-TE is not used in
> >> > production
> >> > > > scenario as SPs have MPLS-VPN as well. for that purpose we require
> >> LDP
> >> > as
> >> > > > well to distribute IGP labels that will be required for PE to PE
> >> > > > communication in case of MPLS-VPN.
> >> > > >
> >> > > > Regards
> >> > > > Sundeep
> >> > > >
> >> > > > On Thu, Feb 2, 2012 at 4:41 PM, Mustafa Yadav <
> >> mustafa.yadav_at_gmail.com
> >> > > >wrote:
> >> > > >
> >> > > >> HD0,
> >> > > >>
> >> > > >>
> >> > > >> In a cisco network I have seen mpls traffic engineneering tunnels
> >> are
> >> > > >> being
> >> > > >> used .So as far as I know rsvp must be configured .But I alos see
> >> that
> >> > > ldp
> >> > > >> is configured in all boxes.why is that?Is not rsvp enough for
> >> > > distrbuting
> >> > > >> labels?
> >> > > >>
> >> > > >>
> >> > > >> Blogs and organic groups at http://www.ccie.net
> >> > > >>
> >> > > >>
> >> >
> _______________________________________________________________________
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> >> >
> >> >
> >> >
> >> >
> >> >
> >> >
> >> >
> >> >
> >>
> >>
> >> --
> >> Problems arise because we talk,problems are not solved because we don't
> >> talk So good or bad talk to your affectionate one's freely.
> >>
> >> Yours Friendly,
> >> H P HEMANTH RAJ
> >> CCIE#28593 (R&S)
> >> Cisco Systems
> >>
> >>
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> >>
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> >>
> >>
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> >>
> >>
> >>
> >>
> >>
> >
> >
> > --
> > With Warmest Regards,
> >
> > CCIE KID
> > CCIE#29992 (Security)
> >
>
> --
> Mobil cihaz}mdan gvnderildi

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Received on Thu Feb 02 2012 - 21:21:54 ART