Indirect Connections - Avaya 8800 Planning And Engineering, Network Design

Layer 3 network design
This configuration uses indirect connections (users are attached to a Layer 2 switch) and direct
connections (users are attached directly to the Ethernet Routing Switch 8800/8600). These
connections are described in following sections.
Both PPPoE and IP traffic flows through the network. Assumptions and configuration requirements
include the following:
• PPPoE packets between users and the ISP are bridged.
• Packets received from the Layer 2 switch are tagged, whereas packets received from the
directly connected user (User 3) are not tagged.
• IP packets between the user and the 8800/8600 are bridged, whereas packets between the
Ethernet Routing Switch 8800/8600 and the routed network are routed.
• VLANs between the Layer 2 switch and the 8800/8600 are port-based.
• VLANS from the directly connected user (User 3) are protocol-based.
• The connection between the Ethernet Routing Switch 8800/8600 and the ISP is a single port
connection.
• The connection between the Layer 2 switch and the Ethernet Routing Switch 8800/8600 can
be a single port connection or a MultiLink Trunk (MLT) connection.
• Ethernet Routing Switch 8800/8600 ports connected to the user side (Users 1, 2, and 3) and
the routed network are routed ports.
• Ethernet Routing Switch 8800/8600 ports connected to the ISP side are bridged (not routed)
ports.

Indirect connections

The following figure shows a switch using routable port-based VLANs for indirect connections.
When configured in this way:
• Port P1 provides a connection to the Layer 2 switch.
Port P1 is configured for tagging. All P1 ingress and egress packets are tagged (the packet
type can be either PPPoE or IP).
• Port P2 provides a connection to the ISP network.
Port P2 is configured for tagging. All P2 ingress and egress packets are tagged (the packet
type is PPPoE).
• Port P3 provides a connection to the routed network.
Port P3 can be configured for either tagging or nontagging (if untagged, the header does not
carry any VLAN tagging information). All P3 ingress and egress packets are untagged (the
packet type is IP).
• Ports P1 and P2 must be members of the same VLAN.
The VLAN must be configured as a routable VLAN. Routing must be disabled on Port P2.
VLAN tagging is preserved on P1 and P2 ingress and egress packets.
June 2016 Planning and Engineering — Network Design
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