Ping local switch cisco

[ziad-chair]

• Le ping vers une interface local ne sort pas du Tx, ce que je veux est courcircuité le tx et le rx du port et envoyé un ping vers l'interface local qui sort forcement du tx et rentre a rxpour tester la qualité transmission sur tous les portions

[Joseph W. Doherty]

Sorry, it's unclear what you're trying to accomplish (possibly due to machine translation).

With that in mind, Cisco devices support extended ping which allows both setting a different source address and/or source routing.  (NB: transit device source routing support is often disabled for "security".)

[ziad-chair]

Hello,

Thank you for your feedback,

Ce que je veux faire est court-circuiter le Tx et le Rx au niveau physique, et envoyer un ping vers l'interface local, si le ping envoyé se transforme en signal sortant du Tx et entrant du Rx peut me qualifier la qualité du fibre u la qualité des répéteurs sur le lien.

[Joseph W. Doherty]

Oh, I suspect you're describing a L1 loopback test.

Such tests are used to verify correct hardware operations.

Pings are not used for this testing, or so I recall (???)).

I've never done such testing, so I cannot advise further.

[Giuseppe Larosa · Accepted solution]

Hello @ziad-chair ,

yes you can connect using a single fiber the TX with RX, depending on the type of interface and device platform you can get an error message looped or you can ping.

Be aware that LAN interfaces do not send ping over wire/fiber so it would be better to connect to another port and using a VRF you can put that other port in the same subnet. At that point you can make a ping test that will qualify the fiber pair.

Edit:

see

https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst9500/software/release/16-12/configuration_guide/rtng/b_1612_rtng_9500_cg/configuring_vrf_lite.html?dtid=osscdc000283

Hope to help

Giuseppe

[ziad-chair]

Hello @Giuseppe Larosa 

Thank you for your feedback it's clear for me and maybe I gonna use this idea

[MHM Cisco World]

Hi you want to ping IP in SW ?

Can you more elaborate?

MHM

[ziad-chair]

Hey,

Je veux qualifier la transmission tout au long d'un chemin optique plein de repeteur, j'ai pensé que je peux forcer le routeur de se comporter comme un "routeur" même avec ces propre paquet donc je boucle le Tx tout en passant par les equipements de transmission optique vers le Rx et lancer le ping pour qualifier s'il y a des pertes sur le chemin ou pas.

[MHM Cisco World]

Sorry can yoh write it in English 

Thanks alot 

MHM

[ziad-chair]

Really??

Use a translation tool.

Anyway I have the appropriate senario, thanks

[Joseph W. Doherty]

Although using VRFs would allow you to indeed have two interfaces with IP interfaces, in the same subnet, on the same device, if you're going to ping between ports on the same device, if your two interfaces have different IP subnets, you wouldn't need VRF.

Don't forget, if looping physical fiber on the same device, some optical transceivers have minimum fiber lengths.

BTW, found this Cisco Hard Plug Loopback Test document which describes using a hardware loopback, on a RJ45 (yet for T1/E1, T3/E3?) and doing ping tests.  Various forms for loopback test were not uncommon back on the older TelCom links.

Also found ASR9000 Ethernet Loopback Testing which does support, on that platform, internal Ethernet loopback and testing with ping.  Possibly other Cisco device offer an internal loopback capability.

Also, I've found one reference to creating a physical copper Ethernet loopback plug.

Create a Loopback Plug for an RJ-45 Ethernet Interface

Action

To create a loopback plug, cross pin 1 (TX+) and pin 3 (RX+) together, and cross pin 2 (TX-) and pin 6 (RX-) together. You need the following equipment to create the loopback:

• A 6-inch long CAT5 cable

• An RJ-45 connector

• A crimping tool

Figure 1 illustrates how to create a loopback plug for an RJ-45 Ethernet interface.

Figure 1: RJ-45 Ethernet Loopback Plug