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Extreme Data Center (VOSS/VSP) study materials
Extreme Data Center (VOSS/VSP) study resources

Extreme Data Center (VOSS/VSP): VLANs, I-SIDs, and Layer 2 Service Provisioning

Extreme Data Center (VOSS/VSP) · Work through your exam, one topic at a time.

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VLANs, I-SIDs, and Layer 2 Service Provisioning

Layer 2 provisioning is the highest-frequency configuration task on VSP, and the exam checks that you separate the local VLAN from the global I-SID.

VLAN basics on VOSS

  • vlan create 100 name 'servers' type port creates a port-based VLAN; vlan members add 100 1/1 adds a port (or mlt 1 for a bundle).
  • Ports are members of VLAN 1 until moved. show vlan confirms membership.
  • A port carries one untagged VLAN and any number of tagged VLANs; tagging is configured per port, not per VLAN.

Mapping to the fabric

  • vlan i-sid 100 10100 binds local VLAN 100 to I-SID 10100. The same I-SID must exist at every participating site; local VLAN IDs may differ.
  • I-SIDs are 24-bit (1-16,777,215). Plan blocks per service type and name them, because show i-sid is your main troubleshooting view.
  • UNI options: a VLAN-to-I-SID mapping (standard L2 VSN), a switched UNI where I-SIDs are assigned per port, a flex UNI where VLANs on the port are carried into the fabric, or a transparent port that maps an entire untagged port to one I-SID.

Worked example

Site A uses VLAN 10 for a server farm; site B uses VLAN 110 for the same subnet. On A: vlan create 10 type port, vlan members add 10 1/1, vlan i-sid 10 10100. On B: vlan create 110 type port, vlan members add 110 1/2, vlan i-sid 110 10100. The hosts see one broadcast domain. If B had used I-SID 10101 instead, both mappings would look correct locally, but show i-sid would show no remote binding at either end and pings would fail. Reasoning: the I-SID, not the VLAN, is the end-to-end key.

Traps

Assuming VLAN IDs must match across sites; adding the I-SID but forgetting to add the access port to the VLAN; configuring the I-SID on BCBs; reusing one I-SID for two services, which merges them into a single broadcast domain; and choosing I-SIDs inside a range already used by Fabric Attach assignments.