Juniper Aggregated Ethernet Interfaces
In this blog, we’ll be discussing one of the most High Availability protocols that’s broadly used in today’s networks that is Link Aggregation Control Protocol (LACP) and Link Aggregation Groups (ALG)
LACP is a method of bundling several physical interfaces to form one logical interface, which is advantageous in providing more bandwidth and increasing redundancy, On Cisco devices this is referred to as Ether-Channel.
It’s worth noting that the load-balancing hash algorithm for IP traffic uses criteria at Layer 2, Layer 3, and Layer 4. No configuration is necessary to enable load balancing. The load-balancing hash algorithm for non-IP traffic uses source and destination MAC addresses.
LACP exchanges are made between actors and partners. An actor is the local interface in an LACP exchange. A partner is the remote interface in an LACP exchange. LACP is defined in IEEE 802.3ad, Aggregation of Multiple Link Segments and was designed to achieve the following:
- Automatic addition and deletion of individual links to the aggregate bundle without user intervention
- Link monitoring to check whether both ends of the bundle are connected to the correct group
Note that the Junos OS implementation of LACP provides link monitoring but not automatic addition and deletion of links.
The LACP mode can be active or passive. By default, when LACP is configured its mode defaults to the passive mode on aggregated Ethernet interfaces. To initiate transmission of LACP packets and response to LACP packets, you must enable LACP active mode.
Note that LACP exchanges protocol data units (PDUs) across all member links to ensure each physical interfaces is configured and functioning properly.
Platform Support for Aggregated Ethernet Interfaces
The following routers support a maximum of 16 physical interfaces per single aggregated Ethernet bundle:
- All MX Series 3D Universal Edge Routers
- All T Series routers
All other routers support a maximum of 8 physical interfaces per aggregated Ethernet bundle.
You can refer to below link for more info about platform support.
Configuring Aggregated Ethernet Links
Specify the number of aggregated Ethernet interfaces to be created:
This process is straightforward if you must configure interfaces ae0, ae1, and ae2 on the router. However, if you must configure only interface ae2 on the local router, the answer is not as simple to ascertain. Although only one aggregated Ethernet interface now exists, you must set the aggregated device count to 3, as setting the aggregated device count to 1 results in the creation of interface ae0—interface ae2 is not created.
Specify the minimum number of links for the aggregated Ethernet interface (aex), that is, the defined bundle, to be labeled up:
The minimum-links statement monitors the member links in the bundle and takes the entire bundle down if the operational member links fall below the configured threshold. You must configure this statement on both ends of the bundle.
Specify the members to be included within the aggregated Ethernet bundle:
Specify an interface family for the aggregated Ethernet bundle:
Configuring Aggregated Ethernet LACP
Configure at least one side of the aggregated Ethernet link as active:
Specify the interval at which the interfaces send LACP packets:
The interval can be fast (every second) or slow (every 30 seconds). You can configure different periodic rates on active and passive interfaces. When you configure the active and passive interfaces at different rates, the transmitter honors the receiver’s rate.
Verify your L3 LACP LAG by viewing the LACP interface status:
root@Switch> show lacp interfaces Aggregated interface: ae0 LACP state Role Exp Def Dist Col Syn Aggr Timeout Activity ge-0/0/0 Actor No No Yes Yes Yes Yes Fast Active ge-0/0/0 Partner No No Yes Yes Yes Yes Fast Passive ge-0/0/1 Actor No No Yes Yes Yes Yes Fast Active ge-0/0/1 Partner No No Yes Yes Yes Yes Fast Passive LACP protocol: Receive State Transmit State Mux State ge-0/0/0 Current Fast periodic Collecting distributing ge-0/0/1 Current Fast periodic Collecting distributing
Use the show lacp statistics interfaces interface-name command to display LACP BPDU exchange information.
You can also use the show interfaces ae0 detail command in user mode. This command will display the member interfaces and member interface statistics.
root@Switch> show interfaces ae0 detail Physical interface: ae0, Enabled, Physical link is Up Interface index: 153, SNMP ifIndex: 553, Generation: 156 Link-level type: Ethernet, MTU: 1514, Speed: 2Gbps, BPDU Error: None, MAC-REWRITE Error: None, Loopback: Disabled, Source filtering: Disabled, Flow control: Disabled, Minimum links needed: 1, Minimum bandwidth needed: 0 Device flags : Present Running Interface flags: SNMP-Traps Internal: 0x0 Current address: 00:23:9c:1a:a3:43, Hardware address: 00:23:9c:1a:a3:43 Last flapped : 2013-09-13 03:54:38 EDT (02:16:40 ago) Statistics last cleared: Never Traffic statistics: Input bytes : 238977 0 bps Output bytes : 994114 0 bps Input packets: 1497 0 pps Output packets: 9294 0 pps IPv6 transit statistics: Input bytes : 0 Output bytes : 0 Input packets: 0 Output packets: 0 Logical interface ae0.0 (Index 93) (SNMP ifIndex 554) (HW Token 4294967295) (Generation 162) Flags: SNMP-Traps 0x0 Encapsulation: ENET2 Statistics Packets pps Bytes bps Bundle: Input : 33 0 2758 0 Output: 39 0 2970 0 Adaptive Statistics: Adaptive Adjusts: 0 Adaptive Scans : 0 Adaptive Updates: 0 Link: ge-0/0/0.0 ge-0/0/1.0 Marker Statistics: Marker Rx Resp Tx Unknown Rx Illegal Rx ge-0/0/0.0 0 0 0 0 ge-0/0/1.0 0 0 0 0 Protocol eth-switch, Generation: 179, Route table: 0 Flags: Trunk-Mode root@Switch>
I hope this was informative and thanks for viewing.