Efps And Mstp; Monitoring Evc - Cisco 3845 - Security Bundle Router Software Manual

Chapter 11 Configuring Ethernet Virtual Connections (EVCs)
Figure 11-12
VLAN tag
After ingress at the EFP with no rewrite, the single tagged packet (VLAN 10) is bridged over
bridge-domain 10. On egress at the switchport, the native VLAN matches the bridge-domain and a
single-tagged (VLAN 10) packet is sent out the switchport.
The same scenario applies when the switchport trunk is configured with the access VLAN ID or native
VLAN ID.
Note Receiving a VLAN-tagged packet where the VLAN is equal to the switchport trunk native VLAN or the
access VLAN is unexpected tagging behavior in switchport-only interactions. However, you can expect
to receive tagged packets equal to the native VLAN or access VLAN when the switchport interacts with
EFPs.

EFPs and MSTP

EFP bridge domains are supported by the Multiple Spanning Tree Protocol (MSTP). These restrictions
apply when running STP with bridge domains.
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Monitoring EVC

Table 11-3 Supported show Commands
Command
show ethernet service evc [id evc-id |
interface interface-id] [detail]
show ethernet service instance [id
instance-id interface interface-id |
interface interface-id] {[detail] | [stats]}
OL-23400-01
Single-tagged Traffic From an EFP with No Rewrite to a Switchport (with Native or
Access VLAN)
Switchport trunk
10 native vlan 10
or
Switchport access
access vlan 10
All incoming VLANs (outer-most or single) mapped to a bridge domain must belong to the same
MST instance or loops could occur.
For all EFPs that are mapped to the same MST instance, you must configure backup EFPs on every
redundant path to prevent loss of connectivity due to STP blocking a port.
When STP mode is PVST+ or PVRST, EFP information is not passed to the protocol. EVC only
supports only MSTP.
Changing STP mode from MST to PVST+ or PVRST for a multicast port is not allowed.
Description
Displays information about all EVCs, or a specific EVC when you enter an EVC
ID, or all EVCs on an interface when you enter an interface ID. The detail
option provides additional information about the EVC.
Displays information about one or more service instance (EFPs). If you specify
an EFP ID and interface, only data pertaining to that particular EFP is displayed.
If you specify only an interface ID, data is displayed for all EFPs on the
interface.
Bridge domain
Service instance 1 ethernet
encapsulation dot1q10
10
bridge-domain 10
Cisco ME 3800X and 3600X Switch Software Configuration Guide
Monitoring EVC
VLAN tag
10
11-29