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Understanding PVLAN Traffic Flows Across Multiple Switches

This topic illustrates and explains three different traffic flows on a sample multiswitch network configured with a private VLAN (PVLAN). PVLANs restrict traffic flows through their member switch ports (which are called “private ports”) so that they communicate only with a specific uplink trunk port or with specified ports within the same VLAN.

This topic describes:

Community VLAN Sending Untagged Traffic

In this scenario, a VLAN in Community-1 of Switch 1 at interface ge-0/0/0 sends untagged traffic. The arrows in Figure 1 represent this traffic flow.

Figure 1: Community VLAN Sends Untagged Traffic

Community VLAN Sends Untagged Traffic

In this scenario, the following activity takes place on Switch 1:

  • Community-1 VLAN on interface ge-0/0/0: Learning
  • pvlan100 on interface ge-0/0/0: Replication
  • Community-1 VLAN on interface ge-0/0/12: Receives traffic
  • PVLAN trunk port: Traffic exits from ge-1/0/2 and from ae0 with tag 10
  • Community-2: Interface receives no traffic
  • Isolated VLANs: Interfaces receive no traffic

In this scenario, this activity takes place on Switch 3:

  • Community-1 VLAN on interface ge-0/0/23 (PVLAN trunk): Learning
  • pvlan100 on interface ge-0/0/23: Replication
  • Community-1 VLAN on interface ge-0/0/9 and ge-0/0/16: Receives traffic
  • Promiscuous trunk port: Traffic exits from ge-0/0/0 with tag 100
  • Community-2: Interface receives no traffic
  • Isolated VLANs: Interfaces receive no traffic

Isolated VLAN Sending Untagged Traffic

In this scenario, isolated VLAN1 on Switch 1 at interface ge-1/0/0 sends untagged traffic. The arrows in Figure 2 represent this traffic flow.

Figure 2: Isolated VLAN Sends Untagged Traffic

Isolated VLAN Sends Untagged Traffic

In this scenario, the following activity takes place on Switch 1:

  • Isolated VLAN1 on interface ge-1/0/0: Learning
  • pvlan100 on interface ge-1/0/0: Replication
  • Traffic exits from pvlan-trunk ge-1/0/2 and ae0 with tag 50
  • Community-1 and Community-2: Interfaces receive no traffic
  • Isolated VLANs: Interfaces receive no traffic

In this scenario, this activity takes place on Switch 3:

  • VLAN on interface ge-0/0/23 (PVLAN trunk port): Learning
  • pvlan100 on interface ge0/0/23: Replication
  • Promiscuous trunk port: Traffic exits from ge-0/0/0 with tag 100
  • Community-1 and Community-2: Interfaces receive no traffic
  • Isolated VLANs: Receive no traffic

PVLAN Tagged Traffic Sent on a Promiscuous Port

In this scenario, PVLAN tagged traffic is sent on a promiscuous port. The arrows in Figure 3 represent this traffic flow.

Figure 3: PVLAN Tagged Traffic Sent on a Promiscuous Port

PVLAN Tagged Traffic
Sent on a Promiscuous Port

In this scenario, the following activity takes place on Switch 1:

  • pvlan100 VLAN on interface ae0 (PVLAN trunk): Learning
  • Community-1, Community-2, and all isolated VLANs on interface ae0: Replication
  • VLAN on interface ae0: Replication
  • Traffic exits from pvlan-trunk ge-1/0/2 with tag 100
  • Community-1 and Community-2: Interfaces receive traffic
  • Isolated VLANs: Receive traffic

In this scenario, this activity takes place on Switch 3:

  • pvlan100 on interface ge-0/0/0: Learning
  • Community-1, Community-2 and all isolated VLANs on interface ge-0/0/0: Replication
  • VLAN on interface ge-0/0/0: Replication
  • Community-1 and Community-2: Interfaces receive traffic
  • Isolated VLANs: Receive traffic
 
 

Published: 2014-04-23

Supported Platforms

 
 

Published: 2014-04-23