The set-overload command sets the overload bit for non-pseudonode LSPs.
The undo set-overload command removes the overload bit of non-pseudonode LSPs.
By default, no overload bit is set for non-pseudonode LSPs.
Format
set-overload [ on-startup [ timeout1 | start-from-nbr system-id [ timeout1 [ timeout2 ] ] | wait-for-bgp [ timeout1 ] ] [ send-sa-bit [ timeout3 ] ] ] [ allow { interlevel | external }* ]
undo set-overload
Parameters
Parameter Description Value
on-startup Indicates that the overload bit remains set within the specified period when the router restarts or is faulty. -
timeout1 Specifies the duration of the overload bit after the system starts. The value is an integer that ranges from 5 to 86400, in seconds. The default value is 600 seconds.
start-from-nbr system-id Specifies the duration of the system overload bit according to the status of a specified neighbor. The value is in XXXX.XXXX.XXXX format.
timeout1 [ timeout2 ] Specifies the period during which the overload bit remains set, which is related to the neighbor status.
If the specified neighbor does not go Up before timeout2 expires, the duration of the system overload bit is timeout2. timeout2 ranges from 5 to 86400, in seconds. The default value is 1200 seconds (20 minutes).
If the specified neighbor goes Up before timeout2 expires, the duration of the system overload bit is timeout1. timeout1 ranges from 5 to 86400, in seconds. The default value is 600 seconds (10 minutes).
wait-for-bgp Specifies the period during which the overload bit of the system remains set according to the BGP convergence status. -
send-sa-bit Specifies the overload bit remains in Hello packets after the device is started. -
timeout3 Specifies the period during which the overload bit remains in Hello packets after the device is started. The value is an integer ranging from 5 to 120, in seconds. The default value is 30 seconds.
allow Allows advertising IP prefixes. By default, the system is prohibited from advertising IP prefixes when the system enters the overload state. -
interlevel Allows advertising the IP prefixes learned from IS-IS of different levels when allow is specified. -
external Allows advertising the IP prefixes learned from other protocols when allow is specified. -
Views
IS-IS view
Default Level
2: Configuration level
Usage Guidelines
Although LSPs with the overload bit are flooded on the network, the LSPs are ignored in the calculation of the routes that pass through the router in overload state. That is, after the overload bit is set on the router, other routers ignore the router when performing SPF calculation. Direct routes of the router are not ignored during SPF calculation.
To prevent the local router from being used by other routers to perform SPF calculation, run the set-overload command on the local router without specifying the on-startup keyword. Then the system immediately sets the overload bit in the LSP to be sent. To remove the overload bit, run the undo set-overload command.
When the local router restarts or is faulty, to prevent the local router from being used by other routers to perform SPF calculation, run the set-overload command on the local router and specify the on-startup keyword.
When the router is experiencing memory shortage, the system automatically sets the overload bit in the sent LSPs regardless of whether the set-overload command is run.
You can set the overload bit to solve the problem of network traffic loss caused by the difference between the BGP convergence speed and IGP convergence speed.
Precautions
If a TE LSP uses the local device as a transit node before the set-overload command is run, the TE LSP is not torn down and re-established and still uses the local device as a transit node after the set-overload command is run; if the local device is restarted after the command is run and fast convergence is not configured on the ingress of the RSVP-LSP, TE LSP forwarding fails, and services are affected. Therefore, the mpls te path-selection overload command needs to be run on the ingress of the RSVP-LSP before the device is restarted.
Example
# Set the overload bit for IS-IS process 1.
<Huawei> system-view
[Huawei] isis
[Huawei-isis-1] set-overload
Warning: The IS-IS process overload state will be set. Continue?[Y/N]
# Configure IS-IS process 1 to enter the overload state during the startup, and configure the local router to remain the overload state for 300 seconds after it establishes the neighbor relationship with neighbor 0000.0000.0002 within 1000 seconds during which the system starts.
<Huawei> system-view
[Huawei] isis
[Huawei-isis-1] set-overload on-startup start-from-nbr 0000.0000.0002 300 1000
# Configure IS-IS process 1 to enter the overload state during the startup, allow IS-IS to advertise the IP prefixes learned from IS-IS of different levels, and prohibit IS-IS from advertising the IP prefixes learned from other protocols.
<Huawei> system-view
[Huawei] isis
[Huawei-isis-1] set-overload on-startup allow interlevel
