Foundry Networks Switch and Router Installation And Configuration Manual page 692

Foundry Switch and Router Installation and Configuration Guide
Table 19.1 lists the maximum total amount of system memory (DRAM) BGP4 can use in software release 07.1.00.
The maximum depends on the total amount of system memory on the device.
Platform
Standard management module (Management I) with 32 MB
Note: This amount also applies to TurboIron/8 and NetIron Stackable Layer 3
Switches with 32 MB.
Management II module with 128 MB
Management II, III, or IV Module with 256 MB
Management IV module with 512 MB
The memory amounts listed in the table are for all BGP4 data, including routes received from neighbors, BGP
route advertisements (routes sent to neighbors), and BGP route attribute entries. The routes sent to and received
from neighbors use the most BGP4 memory. Generally, the actual limit to the number of neighbors, routes, or
route attribute entries the device can accommodate depends on how many routes the Layer 3 Switch sends to
and receives from the neighbors.
In some cases, where most of the neighbors do not send or receive a full BGP route table (about 80,000 routes),
the memory can support a larger number of BGP4 neighbors. However, if most of the BGP4 neighbors send or
receive full BGP route tables, the number of BGP neighbors the memory can support is less than in configurations
where the neighbors send smaller route tables.
As a guideline, Layer 3 Switches with a 512 MB Management IV module can accommodate 150 – 200 neighbors,
with the assumption that the Layer 3 Switch receives about one million routes total from all neighbors and sends
about eight million routes total to neighbors. For each additional one million incoming routes, the capacity for
outgoing routes decreases by around two million.
Memory Configuration Options Obsoleted by Dynamic Memory
Devices that support dynamic BGP4 memory allocation do not require or even support static configuration of
memory for BGP4 neighbors, routes, or route attributes. Consequently, the following CLI commands and
equivalent Web management options are not supported on these devices:
• max-neighbors <num>
• max-routes <num>
• max-attribute-entries <num>
If you boot a device that has a startup-config file that contains these commands, the software ignores the
commands and uses dynamic memory allocation for BGP4. The first time you save the device's running
configuration (running-config) to the startup-config file, the commands are removed from the file.
Configuring BGP4
To begin using BGP4 on the router, follow the steps outlined below:
1. Optionally define the router ID.
2. Enable the BGP4 feature on the router.
3. Set the local AS number.
4. Identify the Foundry Layer 3 Switch's BGP4 neighbors and the ASs they are in.
19 - 10
Table 19.1: Maximum Memory Usage
Maximum Memory BGP4
Can Use
7 MB
62 MB
188 MB
426 MB
December 2000