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Huawei HCIP-Datacom study materials
Huawei HCIP-Datacom study resources

Huawei HCIP-Datacom cheat sheet

Huawei HCIP-Datacom · Keep the key ideas within reach.

Quick reference

Datacom

  • OSPFv2 uses 5 packet types: Hello, DBD, LSR, LSU, LSAck; neighbor states are Down, Attempt, Init, 2-Way, ExStart, Exchange, Loading, Full. Multicast addresses: 224.0.0.5 (AllSPFRouters) and 224.0.0.6 (AllDRouters).

  • OSPF cost = reference bandwidth / interface bandwidth (default ref = 100 Mbps). If cost < 1, it is set to 1. Changing reference bandwidth with 'bandwidth-reference' affects all interfaces; use 'ospf cost' to override per interface.

  • IS-IS uses Level-1 (intra-area), Level-2 (backbone), and Level-1-2 routers. NET address format: AFI (49) + Area ID + System ID (6 bytes) + NSEL (00). DIS election is preemptive; there is no backup DIS.

  • BGP path selection order (Huawei): Weight (highest) > Local Preference (highest) > locally originated > AS_Path (shortest) > Origin (IGP < EGP < Incomplete) > MED (lowest) > EBGP over IBGP > IGP cost to next-hop (lowest) > oldest route > Router ID (lowest) > cluster list length (shortest) > peer address (lowest).

  • BGP route reflectors: a route received from a client is reflected to all clients and non-clients; a route from a non-client is reflected only to clients. Cluster ID prevents loops; Originator ID identifies the original router. Use 'peer reflect-client' under the BGP view.

  • MPLS label stack: outer label is used for forwarding (swap), inner label identifies the VPN (push/pop at PE). PHP (Penultimate Hop Popping) removes the outer label at the penultimate hop; implicit-null (label 3) signals PHP.

  • VXLAN uses a 24-bit VNI (16 million segments) and encapsulates frames in UDP (destination port 4789). VTEPs are identified by IP; BGP EVPN is the control plane for VXLAN in Huawei CloudCampus solutions.

  • QoS classification and marking: 802.1p (CoS) is 3 bits (0-7), DSCP is 6 bits (0-63). Default PHB is 0 (best effort); EF is 46 (low latency); AF classes are AF1x-AF4x. Huawei uses DiffServ domain and traffic behavior/policy.

  • STP/RSTP/MSTP: RSTP port roles are Root, Designated, Alternate, Backup; edge ports use 'stp edged-port'. MSTP maps VLANs to instances; the CIST is instance 0. BPDU guard disables edge ports that receive BPDUs; root guard prevents a port from becoming root.