The MPLS-OPS Archive[Date Prev][Date Next][Thread Prev][Thread Next] [Date Index][Thread Index][Author Index][Subject Index] Re: MPLS over ISDN PRI
All, MPLS over dial-up and ISDN interfaces (both use PPP encap) does work on Cisco AS5xxx NASes, but there are significant caveats for any dial-up implementation of MPLS, never mind RFC2547bis (which is what you seem to want to do) The main problem is that you have no idea where the calls will arrive from the remote sites -- i.e. which channel(s) on which NAS(es). That means the NASes must be configured to dynamically advertise network connectivity within the VRF whenever a CE dials into the NAS. So every time a dial-up site connects or disconnects, MP-BGP has to distribute the new routes and reconverge. The site will have no connectivity until the BGP convergence process is complete -- which can take 40 seconds or more. For a large network with many clients dialing in, and many NASes answering calls, the BGP route churn and slow connectivity is usually a service killer. One way around this is not to run MPLS on the NAS at all, and instead use L2TP to tunnel the PPP session to a BRAS or other PPP aggregation router running MPLS. It can have statically installed routes for the destination (with a higher metric, of course, so they are not used unless the main link is down). There is a Cisco document which describes the L2TP approach as "Remote Access to MPLS Networks". Cheers, Mathew At 05:05 PM 9/10/2002 +0300, Amos Rosenboim wrote: >I personally don't think this is an mpls problem. >I think this is more basic, pri stability issues. >First i would get a stable link between the routers, with the ospf stable >and ipv4 operating , and only then i would go and try to >implement mpls on that link. >As far as stefans remark, i don't know about such a limitation but it's very >much a possibility. >Maybe one of the cisco guys in the list can help in this issue. > > >Thanks >Amos > > > > > >----- Original Message ----- >From: "alok" <alok.dube@apara.com> >To: "Stefan Oettl" <soettl@freenet.de>; <mpls-ops@mplsrc.com> >Sent: Tuesday, September 10, 2002 3:49 PM >Subject: Re: [MPLS-OPS]: MPLS over ISDN PRI > > > > i think Amos made a good point on my last mail....its a PE -CE > > connection..so no need to support MPLS over that. > > > > what you cud do is this: > > is ur calling end have a fixed ip address or a pool (shud be)... > > > > assuming u have a seperate ISDN RAS....u wud have some connectivity b/w >the > > PE and the RAS, u cud use acls on the ethernet connecting to the RAS and >put > > it into the right vrf...or mpls VPN... > > > > similarly...if the call terminates on the PE.. and ISDN interfaces cant be > > directly put onto the vrf, u cud use acls to filter traffic based on >source > > ip and put it into the vrf for that mpls vpn... > > > > i know that filters to vrf mapping seems to work on some routers..not sure > > abt cisco though.... > > > > -rgds > > A > > ----- Original Message ----- > > From: Stefan Oettl <soettl@freenet.de> > > To: Saifulazza <Saifulazza@vads.com>; <mpls-ops@mplsrc.com> > > Sent: Tuesday, September 10, 2002 5:12 PM > > Subject: Re: [MPLS-OPS]: MPLS over ISDN PRI > > > > > > what kind of PE boxes do you use ? > > in case of Cisco's you could configure a backup PE-PE or PE-NAS (NAS will > > need > > MPLS then) GRE tunnel for label switching. > > As far as I know MPLS forwarding on (DDR) ISDN / Dialer interfaces isn't > > supported directly in IOS up to know. Please someone correct me if I'm >wrong > > here ... > > So you could use GRE encapsulation to tunnel the MPLS frames over the > > non-supported circuit. > > > > cheers, > > Stefan > > > > On Tuesday 10 September 2002 11:08, Saifulazza wrote: > > > Hi > > > > > > Has anybody out have implemented the PE-PE connection being backup by > > > ISDN PRI ? . I experienced very unstable connection with the OSPF > > adjacency > > > flapping most of the time and the VPN can never be developed . > > > > > > Cheers > > > > > > > > > > > > -----Original Message----- > > > From: fraanro [mailto:fraanro@arrakis.es] > > > Sent: Tuesday, September 10, 2002 4:02 PM > > > To: Enrique Torres > > > Cc: mpls-ops@mplsrc.com > > > Subject: Re: [MPLS-OPS]: tag-switching MTU on c7206 and c3640 > > > > > > > > > You should configure the tagswitching MTU in the Fast Ethernet > > > interfaces to be able to hold the MPLS frame with as many shim headers > > > as you need. for example 1508 if you want to labels. > > > > > > mpls mtu 1508 > > > > > > under the interface configuration. > > > > > > Rgds. > > > Javier. > > > > > > ----- Mensaje Original ----- > > > Remitente: Enrique Torres <entorresa@yahoo.com> > > > Fecha: Lunes, Septiembre 9, 2002 8:28 pm > > > Asunto: [MPLS-OPS]: tag-switching MTU on c7206 and c3640 > > > > > > > Hi all > > > > > > > > I started tag-switching between 2 nodes of my network > > > > but there is a problem with the MTU and the packet > > > > size after tag imposition. > > > > > > > > My configuration in each node is it > > > > > > > > I have a Cisco7206 (IOS 12.1(1)E), it is connected > > > > with 6 Cisco 3640 (remote cells) through E1 circuits. > > > > Between the C3640 and C7206 I run tag switching > > > > because I have configured VPN's. In all these routers > > > > is configured "Path MTU Discovery" and our MTU between > > > > the c3640 and c7206 is 1530. > > > > > > > > In this configuration I dont have any problem to send > > > > information between clients connected in our c3640's. > > > > > > > > But when I connect this node with a second node, I > > > > must connect the c7206 through a fast ethernet port > > > > and run tag-switching over these ports. In this > > > > situation I started to have problems with http, ftp or > > > > any kind of traffic with large size of packet (greater > > > > than 1500bytes). > > > > > > > > I believe that I have a problem with the MTU after > > > > second tag imposition (the impositon between c7206's) > > > > > > > > Please, could you help me to solve this. > > > > > > > > Thanks, > > > > Enrique. > > > > > > > > > > > > > > > > ===== > > > > Saludos, > > > > Enrique > > > > > > > > __________________________________________________ > > > > Do You Yahoo!? > > > > Yahoo! Finance - Get real-time stock quotes > > > > http://finance.yahoo.com > > > > > > > > ------- > > > > The MPLS-OPS Mailing List > > > > Subscribe/Unsubscribe: http://www.mplsrc.com/mplsops.shtml > > > > Archive: http://www.mplsrc.com/mpls-ops_archive.shtml > > > > > > ------- > > > The MPLS-OPS Mailing List > > > Subscribe/Unsubscribe: http://www.mplsrc.com/mplsops.shtml > > > Archive: http://www.mplsrc.com/mpls-ops_archive.shtml > > > > > > ------- > > > The MPLS-OPS Mailing List > > > Subscribe/Unsubscribe: http://www.mplsrc.com/mplsops.shtml > > > Archive: http://www.mplsrc.com/mpls-ops_archive.shtml > > > > ------- > > The MPLS-OPS Mailing List > > Subscribe/Unsubscribe: http://www.mplsrc.com/mplsops.shtml > > Archive: http://www.mplsrc.com/mpls-ops_archive.shtml > > > > > > > > ------- > > The MPLS-OPS Mailing List > > Subscribe/Unsubscribe: http://www.mplsrc.com/mplsops.shtml > > Archive: http://www.mplsrc.com/mpls-ops_archive.shtml > >------- >The MPLS-OPS Mailing List >Subscribe/Unsubscribe: http://www.mplsrc.com/mplsops.shtml >Archive: http://www.mplsrc.com/mpls-ops_archive.shtml ------- The MPLS-OPS Mailing List Subscribe/Unsubscribe: http://www.mplsrc.com/mplsops.shtml Archive: http://www.mplsrc.com/mpls-ops_archive.shtml
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