Thread: [mpls-linux-general] Problems with MPLS packets
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From: Daniel G. C. <da...@on...> - 2002-04-10 12:25:05
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(sorry for my english) I'm making a MPLS network with PCs with Linux-MPLS 1.0 over kernel 2.4.13 in a Red Hat Linux 7.1 system. I have configured a MPLS network with three PCs and it seems to work properly, but when I use ethereal to capture some packets I watch some problems. I'm testing with ping command, and when I make ping in one way it works properly, it puts the MPLS labels over the IP packets, but in the other way it doesn't put the MPLS labels it sends it as normal IP packets. Also, I have test it with the 2 host network that is in the example of the Linux-MPLS packet, but it continues happenning. ¿Is this a normal behavior of Linux-MPLS? The scenario is: 160.20.20.1 160.20.20.2 A -------------------------------- B eth0 eth1 160.20.20.0 /255.255.252.0 And the mpls configuration is: On A ------- ifconfig eth0 160.20.20.1 netmask 255.255.252.0 up route add -host 160.20.20.2 gw 160.20.20.2 mplsadm -A -B -O gen:10:eth0:ipv4:160.20.20.2 -f 160.20.20.2/32 mplsadm -A -I gen:20:0 mplsadm -L eth0:0 On B ------- ifconfig eth1 160.20.20.2 netmask 255.255.252.0 up route add -host 160.20.20.1 gw 160.20.20.1 mplsadm -A -B -O gen:20:eth0:ipv4:160.20.20.1 -f 160.20.20.1/32 mplsadm -A -I gen:10:0 mplsadm -L eth1:0 The packets from B to A are MPLS, but the replys of ping (or the request of ping) from A to B are not MPLS labeled packets. And when I make ping from B to A, in ethereal (in A) appear Bogus IP headers (I don't know what exactly are they) but they are IP packets with some MPLS labels inside, and after the bogus IP, in ethereal capture, appear the normal IP reply without MPLS label. When I make ping from A to B, in ethereal (in B) appear that the reply from B are MPLS-IP labeled packets, but the requests from A are normal IP packets. And in ethereal (in A) capture list appear that are malformated IP headers (with unknown MPLS labels inside), and after this it sends normal IP packets (the ping reply). The installation in A and B are the same (they are images maked with Norton Ghost), the PCs are exactly the same (the hardware is the same). In A eth0 is a 3Com card, and in B eth1 is a Realtek card but it isn't the problem because I have test it with B and other PC (same hardware and SO installation) that have the same ethernet card in eth1, too, and the problem is the same. Perhaps, Ethereal don't work properly? or, Is this the normal behavior of ping? I don't know why it happens, ¿can someone help me? thanks. Best regards, Dani. |
From: James R. L. <jl...@mi...> - 2002-04-10 12:36:39
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This is a know problem. It is not really a corrupted packet it just look= s that way from ethereal/tcpudmp etc. From the "NOTE" file: -mpls packets appear to be corrupted when running tcpdump or the like on an LER (the packets are not really corrupted, tcpdump is getting an inva= lid version of the packets)=20 Jim On Wed, Apr 10, 2002 at 02:22:00PM +0200, Daniel Gregorio Catalan wrote: > (sorry for my english) > I'm making a MPLS network with PCs with Linux-MPLS 1.0 over kernel 2.4.= 13 in > a Red Hat Linux 7.1 system. I have configured a MPLS network with three= PCs > and it seems to work properly, but when I use ethereal to capture some > packets I watch some problems. > I'm testing with ping command, and when I make ping in one way it works > properly, it puts the MPLS labels over the IP packets, but in the other= way > it doesn't put the MPLS labels it sends it as normal IP packets. > Also, I have test it with the 2 host network that is in the example of = the > Linux-MPLS packet, but it continues happenning. =BFIs this a normal beh= avior > of Linux-MPLS? >=20 > The scenario is: >=20 > 160.20.20.1 160.20.20.2 > A -------------------------------- B > eth0 eth1 >=20 > 160.20.20.0 /255.255.252.0 >=20 > And the mpls configuration is: >=20 > On A > ------- > ifconfig eth0 160.20.20.1 netmask 255.255.252.0 up > route add -host 160.20.20.2 gw 160.20.20.2 > mplsadm -A -B -O gen:10:eth0:ipv4:160.20.20.2 -f 160.20.20.2/32 > mplsadm -A -I gen:20:0 > mplsadm -L eth0:0 >=20 > On B > ------- > ifconfig eth1 160.20.20.2 netmask 255.255.252.0 up > route add -host 160.20.20.1 gw 160.20.20.1 > mplsadm -A -B -O gen:20:eth0:ipv4:160.20.20.1 -f 160.20.20.1/32 > mplsadm -A -I gen:10:0 > mplsadm -L eth1:0 >=20 >=20 > The packets from B to A are MPLS, but the replys of ping (or the reques= t of > ping) from A to B are not MPLS labeled packets. >=20 > And when I make ping from B to A, in ethereal (in A) appear Bogus IP he= aders > (I don't know what exactly are they) but they are IP packets with some = MPLS > labels inside, and after the bogus IP, in ethereal capture, appear the > normal IP reply without MPLS label. >=20 > When I make ping from A to B, in ethereal (in B) appear that the reply = from > B are MPLS-IP labeled packets, but the requests from A are normal IP > packets. And in ethereal (in A) capture list appear that are malformate= d IP > headers (with unknown MPLS labels inside), and after this it sends norm= al IP > packets (the ping reply). >=20 > The installation in A and B are the same (they are images maked with No= rton > Ghost), the PCs are exactly the same (the hardware is the same). In A e= th0 > is a 3Com card, and in B eth1 is a Realtek card but it isn't the proble= m > because I have test it with B and other PC (same hardware and SO > installation) that have the same ethernet card in eth1, too, and the pr= oblem > is the same. >=20 > Perhaps, Ethereal don't work properly? or, Is this the normal behavior = of > ping? I don't know why it happens, =BFcan someone help me? thanks. >=20 > Best regards, Dani. >=20 >=20 > _______________________________________________ > mpls-linux-general mailing list > mpl...@li... > https://lists.sourceforge.net/lists/listinfo/mpls-linux-general --=20 James R. Leu |
From: Daniel G. C. <da...@on...> - 2002-04-10 12:55:09
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Thank you Jim, I saw the 'NOTE' file, but I didn't think that it was = this, because it runs properly in one way but in the other don't (and is = always in the same way). So I thought that it was another diferent problem (perhaps my = configuration, the ethernet cards,...) but if you say that is this, now = I'm good. Thank you. Dani ----- Original Message -----=20 From: James R. Leu=20 To: Daniel Gregorio Catalan=20 Cc: Lista Mpls (envio)=20 Sent: Wednesday, April 10, 2002 4:24 PM Subject: Re: [mpls-linux-general] Problems with MPLS packets This is a know problem. It is not really a corrupted packet it just = looks that way from ethereal/tcpudmp etc. From the "NOTE" file: -mpls packets appear to be corrupted when running tcpdump or the like = on an LER (the packets are not really corrupted, tcpdump is getting an = invalid version of the packets)=20 Jim On Wed, Apr 10, 2002 at 02:22:00PM +0200, Daniel Gregorio Catalan = wrote: > (sorry for my english) > I'm making a MPLS network with PCs with Linux-MPLS 1.0 over kernel = 2.4.13 in > a Red Hat Linux 7.1 system. I have configured a MPLS network with = three PCs > and it seems to work properly, but when I use ethereal to capture = some > packets I watch some problems. > I'm testing with ping command, and when I make ping in one way it = works > properly, it puts the MPLS labels over the IP packets, but in the = other way > it doesn't put the MPLS labels it sends it as normal IP packets. > Also, I have test it with the 2 host network that is in the example = of the > Linux-MPLS packet, but it continues happenning. =BFIs this a normal = behavior > of Linux-MPLS? >=20 > The scenario is: >=20 > 160.20.20.1 160.20.20.2 > A -------------------------------- B > eth0 eth1 >=20 > 160.20.20.0 /255.255.252.0 >=20 > And the mpls configuration is: >=20 > On A > ------- > ifconfig eth0 160.20.20.1 netmask 255.255.252.0 up > route add -host 160.20.20.2 gw 160.20.20.2 > mplsadm -A -B -O gen:10:eth0:ipv4:160.20.20.2 -f 160.20.20.2/32 > mplsadm -A -I gen:20:0 > mplsadm -L eth0:0 >=20 > On B > ------- > ifconfig eth1 160.20.20.2 netmask 255.255.252.0 up > route add -host 160.20.20.1 gw 160.20.20.1 > mplsadm -A -B -O gen:20:eth0:ipv4:160.20.20.1 -f 160.20.20.1/32 > mplsadm -A -I gen:10:0 > mplsadm -L eth1:0 >=20 >=20 > The packets from B to A are MPLS, but the replys of ping (or the = request of > ping) from A to B are not MPLS labeled packets. >=20 > And when I make ping from B to A, in ethereal (in A) appear Bogus IP = headers > (I don't know what exactly are they) but they are IP packets with = some MPLS > labels inside, and after the bogus IP, in ethereal capture, appear = the > normal IP reply without MPLS label. >=20 > When I make ping from A to B, in ethereal (in B) appear that the = reply from > B are MPLS-IP labeled packets, but the requests from A are normal IP > packets. And in ethereal (in A) capture list appear that are = malformated IP > headers (with unknown MPLS labels inside), and after this it sends = normal IP > packets (the ping reply). >=20 > The installation in A and B are the same (they are images maked with = Norton > Ghost), the PCs are exactly the same (the hardware is the same). In = A eth0 > is a 3Com card, and in B eth1 is a Realtek card but it isn't the = problem > because I have test it with B and other PC (same hardware and SO > installation) that have the same ethernet card in eth1, too, and the = problem > is the same. >=20 > Perhaps, Ethereal don't work properly? or, Is this the normal = behavior of > ping? I don't know why it happens, =BFcan someone help me? thanks. >=20 > Best regards, Dani. >=20 >=20 > _______________________________________________ > mpls-linux-general mailing list > mpl...@li... > https://lists.sourceforge.net/lists/listinfo/mpls-linux-general --=20 James R. Leu |