Cisco Cisco Packet Data Gateway (PDG)
System Settings
▀ Configuring ASR 5500 Link Aggregation
▄ ASR 5500 System Administration Guide, StarOS Release 17
70
Configuring ASR 5500 Link Aggregation
A Link Aggregation Group (LAG) works by exchanging control packets via Link Aggregation Control Protocol (LACP)
over configured physical ports with peers to reach agreement on an aggregation of links as defined in IEEE 802.3ad.
The LAG sends and receives the control packets directly on physical ports.
over configured physical ports with peers to reach agreement on an aggregation of links as defined in IEEE 802.3ad.
The LAG sends and receives the control packets directly on physical ports.
Link aggregation (also called trunking or bonding) provides higher total bandwidth, auto-negotiation, and recovery by
combining parallel network links between devices as a single link. A large file is guaranteed to be sent over one of the
links, which removes the need to address out-of-order packets.
combining parallel network links between devices as a single link. A large file is guaranteed to be sent over one of the
links, which removes the need to address out-of-order packets.
LAG and Master Port
Logical port configurations (VLAN and binding) are defined in the master port of the LAG. If the master port is
removed because of a card removal/failure, another member port becomes the master port (resulting in VPN binding
change and outage), unless there is a redundant master port available.
removed because of a card removal/failure, another member port becomes the master port (resulting in VPN binding
change and outage), unless there is a redundant master port available.
Important:
The master port on which VLAN can be created for VPN binding must always be configured on the
active/master MIO/UMIO. The redundancy between MIO/UMIO 5 and MIO/UMIO 6 automatically causes both ports
to be the master with the same VLANs configured and active.
to be the master with the same VLANs configured and active.
LAG and Port Redundancy
ASR 5500 LAG implementation assumes that:
LAG ports on MIO/UMIO 5 and MIO/UMIO 6 are connected to two Ethernet switches.
LAG ports on MIO/UMIO 5 and MIO/UMIO 6 are both active at the same time.
Ports on MIO/UMIO 5 and MIO/UMIO 6 are redundant with each other.
All ports in a LAG can be auto-switched to another MIO/UMIO when certain active port counts or bandwidth
thresholds are crossed.
thresholds are crossed.
LAG and Multiple Switches
This feature connects subscriber traffic ports on MIOs to ports on Ethernet switches. A port failure/switch forces all
ports in a LAG to switch to the other MIO/UMIO when a specified threshold is crossed. This works in a way similar to
the auto-switch feature for port redundancy. LACP runs between the ASR 5500 and the Ethernet switch, exchanging
relevant pieces on information, such as health status.
ports in a LAG to switch to the other MIO/UMIO when a specified threshold is crossed. This works in a way similar to
the auto-switch feature for port redundancy. LACP runs between the ASR 5500 and the Ethernet switch, exchanging
relevant pieces on information, such as health status.
The following table summarizes typical LAG functionality on an MIO/UMIO card.
Table 4. MIO/UMIO LAG Functionality
ASR 5500
LAGID
Ethernet Switch A
Ethernet Switch B
MIO/UMIO Port 11
1
Port 1
----
MIO/UMIO Port 12
1
Port 2
----
MIO/UMIO Port 13
1
----
Port 1