1. LACP/Bundle Communication SR# 638222151
Aditya Kurulkar
HTE (Google)
March 16th 2016

2. Agenda Bundle Processes
Bundle Process/LACP communication RP<->LC
LACP
LACP Function
Bundle Modes
Troubleshooting commands
This slide deck is to address the Concern: LACP/Bundle communication between the LC and RP from SR #

3. What Is A Bundle?
A group of one or more interfaces aggregated together so they can be treated as a single interface by higher layer protocols
Interfaces all directly connected to the same partner device
Also known as a LAG, a Channel Group, a Link Aggregation, a Link Bundle, an Aggregator...
Control Protocol: LACP

4. Bundle Processes Following are the Bundle process running :
Node -> RP:
Bundle MA (BMM) - Bundle Distribution (bundlemgr_distrib)
Bundle Local (BML) - Bundle Local (bundlemgr_local)
Bundle Adjacency - (bundlemgr_adj)
Bundle Checker (BMC) - Process (bundlemgr_checker)
Node -> LC:
Bundle EA (BME) - Bundle Mgr EA (bundlemgr_ea)
Node -> All:
Bundle External Adjacency Manager (BMA)
Legend : (Process_Name)

5. Bundle / LACP Communications:
Bundle MA (BMM):
Processes the configuration; Creates the bundle in IM (Interface Manager)
Replicates a bundle to its members (via IM)
Publishes the BMI attribute
Informing the BML process of per-link information, including LACP state via GSP (Group Services Protocol)
Runs various LACP state machines for bundles and bundle members

6. Bundle MA (BMM): Bundle Config
BMA
Platform DLL
SysDB
BMM
BMA
Bundle
created
BMI attribute published
IM (RP) RP
IM (LC) LC
BMA
Platform DLL
BMA

7. Bundle / LACP Communications:
Bundle Mgr Local - Member Configuration
Bundle Local (BML) runs on all cards where there is bundle-related configuration on local interfaces and processes the configuration
BML notifies the bundle MA(BMM) of the configuration (via GSP) including LACP information.
Bundle MA (BMM) replicates the bundle to the member (via IM)
Bundle EA (BME) calls the platform to:
Create the bundle (if it is not already created) and Add the new bundle member
Bundle MA (BMM) instructs the member interface owner to program the interface (via owner channel)
Runs the LACP state machines relating to LACPDU transmission.
Send and Receive LACPDUs and responding to incoming Marker PDUs

8. Bundle Mgr Local - Member Configuration
BMM
Data Sent to Bundle MA
GSP (RP)
IM (RP) RP
GSP (LC)
IM (LC)
NetIO LC
Bundle Config Processed
Interface programmed
BME
BME
Platform DLL
SysDB
BML
Interface Owner
Bundle replicated to member

9. LACP (LinkAggregationControlProtocol)
The LACP protocol is managed by the Bundle Infrastructure
Bundles can (but do not have to) run the LACP protocol
The LACP protocol is an exchange of packets over the bundle member links.
LACP is used to determine which links of a bundle can carry traffic
LACP functionality is split between RP and LC

10. LACP Functions: LACP ensures :
1. The links in the bundle all terminate on the same partner device
2. The links are all configured to be in the same bundle on the partner device
3. The partner device is likely to be ready to receive traffic on the links
Information is exchanged between devices in LACPDUs (LACP packets) on each link
LACPDUs exchanged periodically as a heartbeat mechanism

11. LAGIDs A Link Aggregation Group consists of either
One or more links such that
1. All links terminate in the same pair of systems
2. All ports belong to the same key group on each system
Membership of a LAG is determined by the LAGID
The LAGID for a link is constructed from the following parameters from the two systems it connects
The system identifier
The (operational) key assigned to the port
The port identifier, if the link is identified as an Individual link
Ports with the same LAGID can be attached to an aggregator (bundle) with a matching key

15. Bundle Modes(LACP):
The Bundle “mode” defines if LACP is sent/received; listen-only or disabled.
“Active”
Bundle Member will always send out periodic LACPDUs to its partner, and will start negotiations when it receives a response.
“Passive”
LACPDUs are only sent if an active LACP partner is believed to be present; i.e. if a LACP packet has been received and is marked to indicate that the partner is "active", and the partner has not timed out. This means that if a link is configured to be "passive" at both ends, the link will not go active
“On”
Does not run LACP on the local link. (Note: these links will be used in forwarding traffic only if all the links in the bundle (local and peer node) are configured to be mode “on”)

16. Troubleshooting Commands:
Bundle and Bundle Members:
show run interface <Bundle>
show interface <Bundle>
show bundle brief
show bundle status detail
show run interface <Bundle Member>
NP Level Info:
show controllers np ports location <Member LC>
show controllers np counters <np#> location <Member LC> [check for BUNDLE_PROTO_PUNT (LACP related)]
show drops np <NP#> location <member LC>
LACP Info:
show lacp counters <Bundle/Member>
show lacp packet-capture <>
show lacp system-id
show lacp <Bundle/Members>
show bundle <Bundle#>
show lacp counters unaccounted <Member LC>

17. Troubleshooting Commands:
Internal:
show gsp stats clien process 130 location <Member LC>
show gsp groups location <Member LC>
show process location <Member LC> | i bund
[Lists the Bundle process on the LC]
show process location 0/rp0/CPU0 | i bund
[Lists the Bundle process on the RP]
Show-tech:
Show tech bundle
Show tech gsp
Show tech sysdb
Debug:
debug lacp packets <Bundle Member> decode
[Checking the LACP exchange between 2 nodes:]
debug bundle infrastructure local all location <member LC>
[LACP communication between LC and RP Bundle process]