Cisco Cisco Packet Data Gateway (PDG)
System Settings
▀ Configuring ASR 5000 Link Aggregation
▄ ASR 5000 System Administration Guide, StarOS Release 18
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Configuring ASR 5000 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 attached to different QGLCs (Quad Gigabit
Line Cards) or XGLCs (10 Gigabit Line Cards).
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 attached to different QGLCs (Quad Gigabit
Line Cards) or XGLCs (10 Gigabit Line Cards).
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.
A LAG can be formed by configuring:
Ports from the same QGLC
Ports from top-bottom QGLCs with port redundancy
Ports from side-by-side XGLCs
Ports from horizontal QGLCs where ports could be from different cards, while some cards could be in L2 (side-
by-side) redundancy.
Important:
LAG cannot be configured when XGLCs have been configured for side-by-side redundancy. A
failure message appears on the CLI when such an attempt is made.
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.
LAG and Port Redundancy
A LAG supports redundant ports, either top-down on the QGLC (vertical link aggregation) or horizontal link
aggregation on the XGLC, when only one port is active in the pair. By default, active ports in a LAG can be on any
XGLC or QGLC, but optionally, all ports in a LAG can be auto-switched to another card when certain active port
counts or bandwidth thresholds are crossed.
aggregation on the XGLC, when only one port is active in the pair. By default, active ports in a LAG can be on any
XGLC or QGLC, but optionally, all ports in a LAG can be auto-switched to another card when certain active port
counts or bandwidth thresholds are crossed.
LAG and Multiple Switches
This feature connects ports on XGLCs or QGLCs to ports on Ethernet switches. A port failure/switch forces all ports in
a LAG to switch to another XGLC or QGLC 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 5000 and the Ethernet switch, exchanging
relevant pieces on information, such as health status.
a LAG to switch to another XGLC or QGLC 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 5000 and the Ethernet switch, exchanging
relevant pieces on information, such as health status.
The following table summarizes typical LAG functionality with QGLCs or XGLCs.