Understanding the Command Components:
This is aHuawei CLI commandused fordiagnosing connectivitywithin aVPN instancein an MPLS network.
ping -aX→ Specifies thesource IP address(X) of the ping packets.
-cY→ Specifies thenumber of ICMP Echo Request packetsto send (Y).
-sZ→ Defines thesize (in bytes) of each ICMP Echo Requestpacket (Z).
-vpn-instance M→ Specifies theVPN instance (VRF) Mto which the ping packets belong.
Why are all options correct?
✅A. The source IP address of the ping packets is X.
The -aX optionforces the ping to originate from IP Xinstead of the default interface IP.
✅B. The ping packets belong to VPN instance M.
The -vpn-instance M optionensures the ping is sent within VPN instance M, allowing verification ofMPLS L3VPN routing.
✅C. During the ping operation, the quantity of ICMP Request packets is Y.
The -cY parameter sets thenumber of ICMP Echo Requeststo be sent, making Y the total count.
✅D. The size of each ICMP Request packet for the ping operation is Z bytes.
The -sZ parameterdefines packet size, helping to testMTU (Maximum Transmission Unit)issues.
Real-World Application:
Verifying MPLS VPN connectivity:Ensure customer networks are reachable withinseparate VRFs.
Testing MTU & fragmentation:Using -sZ, operators can check ifpacket fragmentationoccurs.
Debugging asymmetric routing issues:By forcing -aX, engineers can trace return paths.
✅Reference:Huawei HCIE-Datacom Official Guide – MPLS VPN Troubleshooting & Ping Options
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