Border profiles for Internet peering supports very highly scaled routing tables. This feature is achieved by using hardware optimization by means of an external TCAM (ETCAM) device for Layer 3 routing, as well as by implementing FIB compression.
Note
This feature is applicable only for SLX 9640 devices.Previous releases supported Internet routing tables with limited IPv4 routes after FIB compression and hardware optimization features were enabled. This scale is applicable to Internet routing only on the default VRF.
The FIB compression feature compresses route entries to ensure optimal resource utilization. When there is a more-specific and a less-specific route pointing to a same next-hop, FIB compression addresses the more-specific route and programs only the less-specific route in the hardware.
The hardware optimization feature allows the user to program /24 prefix routes in longest exact match (LEM) table. When this feature is enabled, all /23 routes (split into two /24 routes) and /24 prefix routes are programmed into the LEM table. This feature uses more LEM memory than is required for longest prefix match (LPM), and so can be used on devices that have more LEM than LPM capacity.
SLX 9640 devices support up to 5.7 M IPv4 and 900 K IPv6 internet routes under certain ETCAM profiles when FIB compression is enabled. These profiles can be used at border nodes for Internet peering to support Internet route tables over multiple VRFs.
Profile ETCAM default: This profile programs IPv4 unicast routes into an external lookup device (ELK), and the internal LPM table is used to program IPv6 unicast routes. This is the default profile in the system.
Important
These values are to be viewed as approximate, for design purposes only. They are based on a compression ratio of 30%. The compression ratio is subject to the routes and next-hop combinations that are available in the system, and it may vary from one network design to another. Refer to release notes and scale documentation for further information.| ETCAM profile | FIB compression disabled | FIB compression enabled | ||
|---|---|---|---|---|
| IPv4 unicast routes | IPv6 unicast routes | IPv4 unicast routes | IPv6 unicast routes | |
| profile etcam default | 4,000,000 | 256,000 | 5,700,000 | 365,000 |
| profile etcam ipv6-route | 1,000,000 | 1,000,000 | 1,400,000 | 1,400,000 |
| profile etcam ipv4-ipv6-route | 4,000,000 | 700,000 | 5,700,000 | 900,000 |