Cisco Catalyst 4500 Series - Q Tunneling, VLAN Mapping, and Layer 2 Protocol Tunneling

1-2
Software Configuration Guide—Release IOS XE 3.3.0SG and IOS 15.1(1)SG
OL-25340-01
Chapter 1 Product Overview
Layer 2 Software Features
• Jumbo Frames, page 1-5
• Link Aggregation Control Protocol, page 1-5
• Link Layer Discovery Protocol, page 1-6
• Link State Tracking, page 1-6
• Location Service, page 1-6
• Multiple Spanning Tree, page 1-7
• Per-VLAN Rapid Spanning Tree, page 1-7
• Quality of Service, page 1-7
• Resilient Ethernet Protocol, page 1-8
• SmartPort Macros, page 1-8
• Spanning Tree Protocol, page 1-8
• Stateful Switchover, page 1-9
• SVI Autostate, page 1-9
• Unidirectional Link Detection, page 1-9
• VLANs, page 1-10
• Virtual Switch System Client, page 1-10
• Y.1731 (AIS and RDI), page 1-10
802.1Q Tunneling, VLAN Mapping, and Layer 2 Protocol Tunneling
802.1Q tunneling is a Q-in-Q technique that expands the VLAN space by retagging the tagged packets
that enter the service provider infrastructure. 802.1Q tunneling allows service providers to assign a
VLAN to each customer without losing the original customer VLAN IDs inside the tunnel. All data
traffic that enters the tunnel is encapsulated with the tunnel VLAN ID. Layer 2 Protocol Tunneling is a
similar technique for all Layer 2 control traffic.
To map customer VLANs to service-provider VLANs, you can configure VLAN mapping (or VLAN ID
translation) on trunk ports connected to a customer network. Packets entering the port are mapped to a
service provider VLAN (S-VLAN) based on the port number and the original customer VLAN-ID
(C-VLAN) of the packet.
For information on configuring 802.1Q tunneling and VLAN Mapping, see Chapter 27, “Configuring
802.1Q Tunneling, VLAN Mapping, and Layer 2 Protocol Tunneling.”
Cisco IOS Auto Smartport Macros
Cisco IOS Auto SmartPort macros dynamically configure ports based on the device type detected on the
port. When the switch detects a new device on a port it applies the appropriate Cisco IOS Auto
Smartports macro. When a link-down event occurs on the port, the switch removes the macro. For
example, when you connect a Cisco IP phone to a port, Cisco IOS Auto SmartPorts automatically applies
the IP phone macro. The IP phone macro enables quality of service (QoS), security features, and a
dedicated voice VLAN to ensure proper treatment of delay-sensitive voice traffic.
For information on configuring SmartPort macros, see Chapter 19, “Configuring Cisco IOS Auto
Smartport Macros.”