CARRIER ETHERNET TECHNICAL STANDARD COMPLIANCE REGISTER: VLAN TRUNKING ON CORE ROUTER

EXECUTIVE SUMMARY

This document provides an authoritative technical overview and procedural specification for configuring 802.1Q VLAN Trunking on the CR-Series Carrier-Grade Core Routing Platform. VLAN trunking enables a single physical interface to carry traffic belonging to multiple VLANs, significantly reducing physical port consumption while preserving Layer 2 segmentation across the enterprise backbone. This register outlines hardware prerequisites, the standardized CLI-based configuration workflow, parameter limits, and compliance with IEEE 802.1Q-2022. Intended for network architects and field deployment engineers.

HARDWARE ARCHITECTURE & FORWARDING PLANE SUPPORT

The CR-Series Core Router implements VLAN trunking within the programmable forwarding ASIC (PFA-4th Gen). Each physical interface supports up to 4094 active VLAN trunk instances (VLAN IDs 1–4094) in compliance with IEEE 802.1Q. The hardware performs line-rate tagging, untagging, and tag-preservation without CPU intervention. The internal TCAM (Ternary Content-Addressable Memory) allocates 32,000 entries specifically for VLAN translation and filtering, ensuring zero packet loss during trunk failover events.

KEY FEATURES & ROUTING LOGIC FOR TRUNKING

- 802.1Q Trunk Endpoint (Q-Tag) Support: Native VLAN tagging and stacked VLAN (Q-in-Q) for Metro Ethernet deployments.

- Dynamic Trunk Protocol (DTP) Offload: Hardware-assisted negotiation of trunk mode (desirable/auto/nonegotiate).

- Allowed VLAN List Filtering: Granular per-trunk permit/deny lists (up to 4094 VLAN ranges) with hardware TCAM offload.

- Native VLAN Isolation: Dedicated native VLAN ID assignment with untagged frame handling (default VLAN 1 reassignable).

- Trunk Failover Mechanism: Bidirectional Forwarding Detection (BFD) coupled with trunk link redundancy (sub-50 ms).

CONFIGURATION WORKFLOW (CLI-BASED)

Step 1 – Access Global Configuration Context

# configure terminal

Step 2 – Select Physical Interface (e.g., HundredGigE 0/0/0)

(config)# interface hundredGigE 0/0/0

Step 3 – Set Interface as Trunk

(config-if)# switchport mode trunk

Step 4 – Define Native VLAN (Optional, default = VLAN 1)

(config-if)# switchport trunk native vlan 10

Step 5 – Specify Allowed VLANs (Default = all VLANs 1–4094)

(config-if)# switchport trunk allowed vlan add 100,200-300,1000

Step 6 – Verify Configuration

# show interfaces hundredGigE 0/0/0 trunk

OPERATIONAL ADVANTAGES

Implementing VLAN trunking on the CR-Series reduces infrastructure complexity by 70% in typical core-to-distribution links, lowers power consumption per Gbps transported, and enables seamless VM mobility across data center racks without re-cabling. Hardware-native tag manipulation guarantees wire-speed forwarding at 800 Gbps per slot.

COMPLIANCE & STANDARDS

- IEEE 802.1Q-2022 (VLAN Tagging & Trunking)

- IEEE 802.1ad (Provider Bridging – Q-in-Q)

- MEF 6.2 (Ethernet Private Line Services)

- ITU-T G.8011/Y.1307 (Ethernet over Transport)

TECHNICAL SPECIFICATIONS

ORDERING SKU INFORMATION

CR-SERIES TRUNK ENABLEMENT: Standard with base software license (no additional SKU).

Optional advanced trunk features (VLAN translation, selective Q-in-Q): SKU – CR-VLAN-ADV.

Recommended optics for trunk uplinks: CR-SFP28-25G-LR, CR-QSFP56-100G-ER4.

DEPLOYMENT TOPOLOGY NOTE: For core-to-aggregation trunking, ensure native VLAN matches on both sides. For multi-vendor interoperability, set switchport trunk encapsulation dot1q explicitly (legacy ISL not supported).

REVISION HISTORY

Version 1.0 – Engineering Release – Validated on CR-8808 with CR-OS 6.2.1.