The 7705 SAR supports Link Aggregation Groups (LAGs) based on the IEEE 802.1ax standard (formerly 802.3ad). Link aggregation provides:
increased bandwidth by combining multiple links into one logical link (in active/active mode)
load sharing by distributing traffic across multiple links (in active/active mode)
redundancy and increased resiliency between devices by having a standby link to act as backup if the active link fails (in active/standby mode)
In the 7705 SAR implementation, all links must operate at the same speed.
Packet sequencing must be maintained for any given session. The hashing algorithm deployed by Nokia routers is based on the type of traffic transported to ensure that all traffic in a flow remains in sequence while providing effective load sharing across the links in the LAG. See LAG and ECMP Hashing for more information.
LAGs must be statically configured or formed dynamically with Link Aggregation Control Protocol (LACP). See LACP and Active/Standby Operation for information on LACP.
All Ethernet-based supported services can benefit from LAG, including:
network interfaces and SDPs
spoke SDPs, mesh SDPs, and EVPN endpoints
IES and VPRN interfaces and SAPs
Ethernet and IP pseudowire SAPs
routed VPLS (r-VPLS) SAPs
LAGs are supported on access, network, and hybrid ports. A LAG can be in active/active mode or in active/standby mode for access, network, or hybrid ports. Active/standby mode is a subset of active/active mode if subgroups are enabled.
LAGs are supported on access ports on the following:
8-port Gigabit Ethernet Adapter card
10-port 1GigE/1-port 10GigE X-Adapter card (10-port GigE mode)
6-port Ethernet 10Gbps Adapter card
4-port SAR-H Fast Ethernet module
6-port SAR-M Ethernet module
Packet Microwave Adapter card (for ports not in a microwave link)
all fixed platforms
LAGs are supported on network ports on the following:
8-port Gigabit Ethernet Adapter card
10-port 1GigE/1-port 10GigE X-Adapter card
6-port Ethernet 10Gbps Adapter card
4-port SAR-H Fast Ethernet module
6-port SAR-M Ethernet module
Packet Microwave Adapter card (for ports not in a microwave link and ports in a 1+0 network microwave link; LAGs are not supported on ports in a 1+1 HSB microwave link)
all fixed platforms
LAGs are supported on hybrid ports on the following:
8-port Gigabit Ethernet Adapter card
10-port 1GigE/1-port 10GigE X-Adapter card (10-port GigE mode)
6-port Ethernet 10Gbps Adapter card
6-port SAR-M Ethernet module
Packet Microwave Adapter card (for ports not in a microwave link)
all fixed platforms
On access ports, a LAG supports active/active and active/standby operation. For active/standby operation the links must be in different subgroups. Links can be on the same platform or adapter card/module or distributed over multiple components. Load sharing is supported among the active links in a LAG group.
On network ports, a LAG supports active/active and active/standby operation. For active/standby operation the links must be in different subgroups. Links can be on the same platform or adapter card/module or distributed over multiple components. Load sharing is supported among the active links in a LAG group. Any tunnel type (for example, IP, GRE, or MPLS) transporting any service type, any IP traffic, or any labeled traffic (LER, LSR) can use the LAG load-sharing, active/active, and active/standby functionality.
LAGs are supported on network 1+0 microwave links. Ports that are in a microwave link can be added to the same LAG as ports that are not in a microwave link. Ports belonging to a microwave link must have limited autonegotiation enabled before the link can be added to a LAG.
A LAG that contains ports in a microwave link must have LACP enabled for active/standby operation. Static LAG configuration (without LACP) is not supported for active/standby LAGs with microwave-enabled ports.
On hybrid ports, a LAG supports active/active and active/standby operation. For active/standby operation the links must be in different subgroups. Links can be on the same platform or adapter card/module or distributed over multiple components. Load sharing is supported among the active links in a LAG group.
A LAG group with assigned members can be converted from one mode to another as long as the number of member ports are supported in the new mode and the ports all support the new mode, none of the members belong to a microwave link, and the LAG group is not associated with a network interface or a SAP.
A subgroup is a group of links within a LAG. On access, network, or hybrid ports, a LAG can have a maximum of four subgroups and a subgroup can have links up to the maximum number supported on the LAG. The LAG is active/active if there is only one sub-group and is active/standby if there is more than one subgroup.
When configuring a LAG, most port features (port commands) can only be configured on the primary member port. The configuration, or any change to the configuration, is automatically propagated to any remaining ports within the same LAG. Operators cannot modify the configurations on non-primary ports. For more information, see Configuring LAG Parameters.
If the LAG has one member link on a second-generation (Gen-2) Ethernet adapter card and the other link on a third-generation (Gen-3) Ethernet adapter card or platform, a mix-and-match scenario exists for traffic management on the LAG SAP. In this case, all QoS parameters for the LAG SAP are configured but only those parameters applicable to the active member link are used. See LAG Support on Mixed-Generation Hardware for more information.
Configuring a multiservice site (MSS) aggregate rate can restrict the use of LAG SAPs. For more information, refer to the ‟MSS and LAG Interaction on the 7705 SAR-8 Shelf V2 and 7705 SAR-18” section in the 7705 SAR Quality of Service Guide.