Skip to main content

Juniper Junos

Routing-table collection on Junos​

Junos devices can have very large RIB tables — sometimes in the millions of routes. The Forward Collector offers two ways to control how much of that data is collected:

  • An organization-wide RIB route limit.
  • A per-device choice of BMP vs. CLI for BGP routes.

RIB route limit​

Configure under Platform → Collectors → Organization collection settings → Advanced → RIB collection. The same fields apply to Arista, Cisco IOS / IOS-XE / IOS-XR / NX-OS, and Juniper Junos.

FieldEffect
Max number of routesIf a device's RIB exceeds this number, only routes whose subnets appear in Required subnets are collected. The default route is always collected. Leave empty to collect all routes.
Required subnetsSubnets to always collect when the limit is exceeded, one per line. Both IPv4 and IPv6 are supported.
VRF/routing instance name filtersGlob patterns; if non-empty, Required subnets applies only to matching VRFs. For non-matching VRFs, all routes are collected.

On Junos, the RIB route limit affects BGP routes collected via CLI. IGP and static routes are not affected.

RIB collection settings

BMP vs. CLI for BGP​

CLI-based BGP collection scales poorly past a few hundred thousand routes. For large internet-edge deployments, BMP collection is recommended — it streams BGP RIB data over a peer connection and avoids the CLI cost entirely. Per-device BMP behavior is configured under Sources → Devices → Edit Device → Advanced Settings.

When BMP is enabled, BGP routes come from BMP and the org-level RIB route limit applies only to IGP and static routes collected via CLI.

FIB collection​

If a device reports both RIB and FIB data, the Forward Platform prefers FIB. The collector no longer chunks FIB collection on Junos. There is no per-platform FIB cutoff knob — overall scale is governed by the RIB route limit above.

BGP route selection​

Forward implements BGP route selection consistent with Juniper's documentation on route selection.