Local Switching on Junos Fusion Provider Edge
Junos Fusion supports packet forwarding both on the aggregation device and on satellite devices. The default behavior is to forward the packets received on the extended port to the aggregation device. The satellite device does not perform any processing on the incoming traffic. The aggregation device processes and directs the data traffic.
Local switching in Junos Fusion reduces the traffic that is exchanged between satellite devices and the aggregation device by handling some of the local switching. When you enable local switching, the satellite device handles the bridging traffic locally on the satellite device. The satellite device maintains a bridge forwarding table with the local MAC addresses for devices that are connected directly to the satellite device and forwards the data packets with local MAC addresses. Packets with unknown MAC addresses are sent to the aggregate device. Local switching applies to all the ports on the satellite device.
To configure local switching on a satellite device, include
the local-switching statement in the forwarding options
hierarchy:
[edit forwarding-options]
satellite {
fpc slot {
local-switching;
}
}
Selective VLAN Local Switching
In some cases, you might want to enable local switching for only a select number of VLANs on the satellite device–for example, offloading data traffic based on the type of service. This will allow you to control traffic more precisely. To enable selective VLAN local switching on a satellite device, include selected VLANs in a virtual switch routing instance. VLANs that are not included in the routing instance will default to forwarding data packets to the aggregate device.
To configure selective VLAN local switching on a satellite device,
include the selective-vlan-switching statement in the
forwarding options hierarchy with a virtual switch routing instance:
[edit forwarding-options]
satellite {
fpc slot {
selective-vlan-switching {
routing-instance routing-instance-name;
}
}
}
When you have digital subscriber line access multiplexer (DSLAM)
ports and broadband network gateway (BNG) ports on a satellite device,
you should configure the satellite device to switch traffic locally
from the DSLAM ports to the BNG port while restricting the traffic
between two DSLAM ports. Configure the satellite device to switch
traffic locally from a DSLAM port to a BNG port by including the core-facing keyword in all BNG port interfaces. Restrict switched
traffic between DSLAM ports by including the no-local switching keyword in the bridge domain.
Policer
Traffic policing enables you to control the maximum rate of traffic that will be sent or received on an interface. A policer defines a set of traffic rate limits and sets the action for traffic that does not conform to the configured limits. Packets in a traffic flow that do not conform to traffic limits are either discarded or are marked with a different forwarding class or packet loss priority (PLP) level.
You can limit the flow of Layer 2 traffic that is sent to the
aggregation device by applying an ingress policer at the satellite
device. You configure the Layer 2 ingress policer by using the input-policer statement at the [edit interfaces interface-name
layer2-policer] hierarchy level. Because the satellite device
is only aware of locally switched logical interface, the ingress policer
is applied to Layer 2 input traffic at the satellite device ports.
Example: Configuring Selective VLAN Local Switching
In this configuration example, the satellite device is configured with the following options:
VLANs 101, 102, 103, and 104 are enabled for selective VLAN local switching.
VLAN 101 and 102 have DSLAM traffic.
Interface xe-100/0/0 is a BNG port.
Interfaces xe-100/0/1 and xe-100/0/2
interfaces {
xe-100/0/0 {
unit 0 {
family bridge {
interface-mode trunk;
vlan-id-list [100-110];
core-facing;
}
}
}
xe-100/0/1 {
layer2-policer {
input-policer SD-policer-A;
}
unit 0 {
family bridge {
interface-mode trunk;
vlan-id-list [100-110];
}
}
}
xe-100/0/2 {
layer2-policer {
input-policer SD-policer-A;
}
unit 0 {
family bridge {
interface-mode trunk;
vlan-id-list [100-110];
}
}
}
}
routing-instances {
vs-1 {
instance-type virtual-switch;
interface xe-100/0/0.0;
interface xe-100/0/2.0;
interface xe-100/0/2.0;
bridge-domains {
bd-1 {
vlan-id 101;
no-local-switching;
}
bd-2 {
vlan-id 102;
no-local-switching;
}
bd-3 {
vlan-id 103;
}
bd-4 {
vlan-id 104;
}
}
}
forwarding-options {
satellite {
fpc 100 {
sd-vlan-switching {
routing-instance vs-1;
}
}
}
}
}