1GB surpasses Cisco's recommendation of 512MB for the full BGP table but there are caveats at play, are you using IOS firewall, IPS, NAT, QoS, ACL's, multicast, netflow, IPSec, cef transit traffic at peak - this would hike the requirements up
I did a dual 3945E ISR implementation where I used the upgrade module from 1GB to 4GB SDRAM as we were using many of the features above, no problems so far Second Marc's point on soft reconfig, great point! -- BR Tony Sent from my iPad > On 2 Jan 2014, at 16:12, marc abel <[email protected]> wrote: > > You do not need BGP soft-reconfiguration as of IOS 12.0 so that should save > you some memory. > > http://www.cisco.com/en/US/products/ps6599/products_data_sheet09186a0080087b3a.html > > Previously, in order to perform a soft reset for inbound routing table > updates, the neighbor soft-reconfiguration command directed the Cisco IOS > software in the local BGP router to store all received (inbound) routing > policy updates without modification. This method is memory-intensive and > not recommended unless absolutely necessary. (Outbound updates have never > required the extra memory and are not affected by this feature.) > > With this software release, the BGP Soft Reset Enhancement feature provides > automatic support for dynamic soft reset of inbound BGP routing table > updates that is not dependent upon stored routing table update information. > The new method requires no preconfiguration (as with the neighbor > soft-reconfiguration command) and requires much less memory than the > previous soft reset method for inbound routing table updates. > > >> On Thu, Jan 2, 2014 at 9:51 AM, Ryan Jensen <[email protected]> wrote: >> >> Morning! >> I have an OT question... >> I have two 40mbps internet connections from the same ISP today, each one >> runs into a 2921 router. I receive a default route via eBGP with ISP and >> the two routers peer via iBGP with each other. I'm going to be dropping one >> internet connection soon and picking up a second ISP, same bandwidth. We're >> just doing this to diversify. >> Question is: Would the 2921s have enough resources to accept full internet >> tables from each ISP? >> The way I look at it, each router would store the BGP table from the ISP, >> and also store the table from its iBGP peer... with soft-reconfiguration >> enabled, It then stores a second copy of each peer's updates. Basically >> requiring the router to store the entire internet BGP table 4 times... Am I >> looking at this correctly? >> >> I know my current ISP has an option for them to advertise their originated >> routes (core routes) and a default, so that would significantly decrease >> the update size from that peer, but I don't know if my incoming ISP has >> that option. >> >> Routers are default hardware spec, 1g RAM, 256mb Flash >> IOS 15.2(4)M3 >> >> Thoughts?? >> _______________________________________________ >> Free CCIE R&S, Collaboration, Data Center, Wireless & Security Videos :: >> >> iPexpert on YouTube: www.youtube.com/ipexpertinc > > > > -- > Marc Abel > CCIE #35470 > (Routing and Switching) > _______________________________________________ > Free CCIE R&S, Collaboration, Data Center, Wireless & Security Videos :: > > iPexpert on YouTube: www.youtube.com/ipexpertinc _______________________________________________ Free CCIE R&S, Collaboration, Data Center, Wireless & Security Videos :: iPexpert on YouTube: www.youtube.com/ipexpertinc
