[c-nsp] reacheability issue in MEL link
Ahmed Mohamed
ahmedazim at gmail.com
Thu Feb 5 05:10:39 EST 2009
Hi,
just wanted to share with you,
i found the problem in a damaged port,the port is in Fast Ethernet Module :
PA-2FE-TX
the funny thing is that the interfaces goes "up-up" when a cable plugged,
and "down-down" when unplugged, and the Field Engineer confirmed LED shows
normal operation, but the port wouldn't ping !!!
when i moved the circuit to the second port in the module, the ping came
successful
so beware of this tricky fault, always try another port ;)
On Wed, Feb 4, 2009 at 5:48 PM, Matt Carter <matt at iseek.com.au> wrote:
> hi,
>
>
> <off-list>
>
> my advice , check to see if the SP is actually giving you a service which
> you can do trunking on (ie, they have vlan stacking aka dot1q enabled)
>
> if that is the case, ensure you have the vlan dot1q tag native command
> enable to ensure all frames for all vlans are tagged (otherwise the native
> vlan will be untagged) that seems to cause some problem for some carriers
> (getting a mix of vlan colored/uncolored packets)
>
> and yes it is common for failure in the carrier network not to be reflected
> at the switch port you are connected to, enable UDLD or BFD to pick up holes
> in the middle..
>
> > -----Original Message-----
> > From: cisco-nsp-bounces at puck.nether.net [mailto:cisco-nsp-
> > bounces at puck.nether.net] On Behalf Of Ahmed Mohamed
> > Sent: Thursday, 5 February 2009 1:15 AM
> > To: Ahmed Maged (amaged)
> > Cc: cisco-nsp at puck.nether.net
> > Subject: Re: [c-nsp] reacheability issue in MEL link
> >
> >
> <CE>--------------------------------Metroethernet(carrier)----------------
> > -----<switch>----ethernet(cable)-----<PE>
> >
> > for a link as simple as above, if :
> > + the CE , the Agg. switch and the PE interfaces are in the same vlan
> > + the CE and the PE IP interfaces are in the same subnet
> >
> > the i must (at least) have an entry in arp table, and ping successful,
> > which
> > is not the case
> >
> > what was getting me crazy , is that all interfaces are up-up all the
> time,
> > but i just recieved a feedback today that MetroEthernet carriers have
> > NTU's
> > acting as Ethernet HUB, so as long as they are functional , you will have
> > the interfaces up-up even if the circuit is broken inside the carrier !!!
> >
> > tomorrow i will order dual dispatch to both ends, will test circuit
> > termination at both ends
> >
> > "traceroute mac" feature is not in CE or PE IOS
> >
> >
> >
> > On Wed, Feb 4, 2009 at 1:25 PM, Ahmed Maged (amaged)
> > <amaged at cisco.com>wrote:
> >
> > > Troubleshoot layer by layer.
> > >
> > > If the lower layers doesn't work, don't expect anything to behave
> > > properly.
> > >
> > > Follow the L2 frame with (ltrace) if available on your IOS.
> > >
> > > How about debugging?
> > >
> > > Can you install a sniffer?
> > >
> > > What do you see on the interfaces counters?
> > >
> > > Did you try anything else other than ping, maybe ICMP is blocked.
> > >
> > > -----Original Message-----
> > > From: cisco-nsp-bounces at puck.nether.net
> > > [mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Ahmed Mohamed
> > > Sent: Tuesday, February 03, 2009 2:28 AM
> > > To: cisco-nsp at puck.nether.net
> > > Subject: [c-nsp] reacheability issue in MEL link
> > >
> > > Hello,
> > >
> > > this is a real life problem still occuring, and have no idea what may
> be
> > > causing it ..
> > >
> > > we are providing an internet direct service to our customer vial MEL
> > > (Metro
> > > Ethernet Link)
> > >
> > > CE (CS-7206 VXR) fe2/0.36 ------------------Etherlink(local
> > > carrier)---------------- WS-3759G-24TS--PE(CS-7000)
> > >
> > > the solution is providied using a carrier to link the customer CE to an
> > > aggregated switch, using Metro Ethernet
> > > configuring vlan 36 and using dot1q encapsulation
> > > then from the aggregating switch to the PE router using also
> > > encapsulation
> > > dot1q for vlan36
> > >
> > > all interfaces are up-up , and still ping fails !!
> > >
> > > i tried everything, resetting ports, switches, reconfigure interfaces
> > > ..etc.
> > > still no joy
> > >
> > > any idea what could be causing the problem ?
> > >
> > >
> ========================================================================
> > > CE:
> > > -----
> > > interface FastEthernet2/0.36
> > > bandwidth 61440
> > > encapsulation dot1Q 36
> > > ip address 57.78.2.6 255.255.255.252
> > >
> ========================================================================
> > > Agg. switch:
> > > ------------------
> > > interface GigabitEthernet1/0/9
> > > switchport trunk encapsulation dot1q
> > > switchport trunk native vlan 3109
> > > switchport trunk allowed vlan 36,3109
> > > switchport mode trunk
> > > switchport nonegotiate
> > > duplex full
> > > speed 100
> > > mls qos trust cos
> > > spanning-tree bpdufilter enable
> > >
> ========================================================================
> > > PE:
> > > ------
> > > interface FastEthernet5/1/1.36
> > > bandwidth 61440
> > > encapsulation dot1Q 36
> > > ip address 57.78.2.5 255.255.255.252
> > > no ip redirects
> > > no ip proxy-arp
> > > no ip route-cache
> > > no cdp enable
> > >
> ========================================================================
> > > bmil305#sh int FastEthernet5/1/1.36
> > > FastEthernet5/1/1.36 is up, line protocol is up <<<<<<
> > > Hardware is cyBus FastEthernet Interface, address is 0003.fe91.b8a9
> (bia
> > > 0003.fe91.b8a9)
> > > Internet address is 57.78.2.5/30
> > > MTU 1500 bytes, BW 61440 Kbit, DLY 100 usec,
> > > reliability 255/255, txload 1/255, rxload 1/255
> > > Encapsulation 802.1Q Virtual LAN, Vlan ID 36.
> > > ARP type: ARPA, ARP Timeout 04:00:00
> > >
> ========================================================================
> > > pmil2534#sh int Fa2/0.36
> > > FastEthernet2/0.36 is up, line protocol is up <<<<<<
> > > Hardware is i82543 (Livengood), address is 0022.be8b.1038 (bia
> > > 0022.be8b.1038)
> > > Description: --- To bmil305 - FE5/1/1.5
> > > Internet address is 57.78.2.6/30
> > > MTU 1500 bytes, BW 61440 Kbit, DLY 100 usec,
> > > reliability 255/255, txload 1/255, rxload 1/255
> > > Encapsulation 802.1Q Virtual LAN, Vlan ID 36.
> > >
> ========================================================================
> > > ping pe to CE fails:
> > > ----------------------------
> > > bmil305#ping 57.78.2.6 <<<<<<,
> > > Type escape sequence to abort.
> > > Sending 5, 100-byte ICMP Echos to 57.78.2.6, timeout is 2 seconds:
> > > .....
> > > Success rate is 0 percent (0/5)
> > >
> ========================================================================
> > > PE to internet (google) successfully:
> > > ------------------------------------------------------
> > > bmil305#ping 216.239.59.147 source fast 5/1/1.36 repeat 100 size 500
> > > Type escape sequence to abort.
> > > Sending 100, 500-byte ICMP Echos to 216.239.59.147, timeout is 2
> > > seconds:
> > > Packet sent with a source address of 57.78.2.5
> > > !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
> > > !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
> > > Success rate is 100 percent (100/100), round-trip min/avg/max =
> > > 36/40/112 ms
> > >
> ========================================================================
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