Memory Considerations; Configuring Bgp4 - Dell PowerConnect B-RX Configuration Manual

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Memory considerations

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Memory considerations
BGP4 handles a very large number of routes and therefore requires a lot of memory. For example,
in a typical configuration with just a single BGP4 neighbor, a BGP4 router may need to be able to
hold up to 150,000 routes. Many configurations, especially those involving more than one
neighbor, can require the router to hold even more routes. The device provide dynamic memory
allocation for BGP4 data. These devices automatically allocate memory when needed to support
BGP4 neighbors, routes, and route attribute entries. Dynamic memory allocation is performed
automatically by the software and does not require a reload.
As a guideline, BigIron RX switches with a 2 GB Management 4 module can accommodate 150 –
200 neighbors, with the assumption that the device 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.

Configuring BGP4

Once you activate BGP, you can configure the BGP options. On a BigIron RX there are two
configuration levels: global and address family.
At the global level, all BGP configurations apply to IPv4 and IPv6. You enter this layer using the
router bgp command.
Under the global level, you specify an address family. Address families separate the IPv4 and IPv6
BGP configuration. You enter this level by entering the address-family command at the router bgp
level. The command requires you to specify the IPv4 or IPv6 network protocol.
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RFC 2439 (Route Flap Dampening)
RFC 2796 (Route Reflection)
RFC 2842 and 3392 (Capability Advertisement)
RFC 3065 (BGP4 Confederations)
RFC 2858 (Multiprotocol Extensions)
RFC 2918 (Route Refresh Capability)
RFC 3392 (BGP Capability Advertisement)
BigIron RX Series Configuration Guide
53-1001810-01