BGP Prefix Count vs Route LIst load times

RouterOS Forwarding Protocols
1

Hi Guys,

I know this has been covered a million times in different ways but I am still unclear so Id like to ask some direct questions to help get a better understanding.

  1. When I fire up a peer in my MikroTik router, it downloads 713613 Prefixs in around 20 seconds. I see this under Routing > BGP > Peers > Prefix Count
  2. Then when I go to IP > Route and click “show full route list” it takes a further 10mins or so to load 713611 items.

Regarding point 1. When it has downloaded the prefixes, is that the router good to go? Is it now in an up and running state? Or does it have to do the loading of the route list in the background which means it will actually be another 10mins before its ready to go?

Regarding point 2, is this important to when the router can actually begin routing or is this only impacting my ability to search?

Which point would be relevant for convergence time if a peer dropped off and came back? Would the 20second load time reflect the time it takes the router to sort itself out or would the 10min route list load time reflect the time it takes the router to sort itself out?

There is so much talk of BGP being slow on MT routers, however, if the time for the peer to load the Prefix Count is all I really need to worry about then I’m totally chuffed with 20 seconds, I actually think that’s ace. If my limitation is waiting for the Route List to load then that’s OK with me.

The last question, couldn’t the router just keep the route list always loaded? This would save it loading each time someone wants to use it for a search?

Thanks guys

2

The longer load time is primarily due to the information being sent to Winbox and it dynamically updating the route display as it populates the data. Would be miles faster to snapshot and transfer the routing table data and for Winbox to subsequently display the information.

3

Are you filtering prefixes? Full public internet tables can be resource drain when:

  • Clearing BGP communities used within your network
  • Filtering IPv4 and IPv6 bogons
  • Filtering your own and downstream customer prefixes
  • Appending BGP community values, setting local preference and setting weight so that route reflectors failover faster
  • Local preference is reduced when reflecting route to out of region route reflectors (eg in another data centre)


    Herewith just the bogon filter:
add action=discard chain=rfc1918 comment="Special-Use IPv4 Addresses:" prefix=0.0.0.0/8 \
    prefix-length=8-32
add action=discard chain=rfc1918 prefix=10.0.0.0/8 prefix-length=8-32
add action=discard chain=rfc1918 prefix=100.64.0.0/10 prefix-length=10-32
add action=discard chain=rfc1918 prefix=127.0.0.0/8 prefix-length=8-32
add action=discard chain=rfc1918 prefix=169.254.0.0/16 prefix-length=16-32
add action=discard chain=rfc1918 prefix=172.16.0.0/12 prefix-length=12-32
add action=discard chain=rfc1918 prefix=192.0.0.0/24 prefix-length=24-32
add action=discard chain=rfc1918 prefix=192.0.2.0/24 prefix-length=24-32
add action=discard chain=rfc1918 prefix=192.88.99.0/24 prefix-length=24-32
add action=discard chain=rfc1918 prefix=192.168.0.0/16 prefix-length=16-32
add action=discard chain=rfc1918 prefix=198.18.0.0/15 prefix-length=15-32
add action=discard chain=rfc1918 prefix=198.51.100.0/24 prefix-length=24-32
add action=discard chain=rfc1918 prefix=203.0.113.0/24 prefix-length=24-32
add action=discard chain=rfc1918 prefix=224.0.0.0/4 prefix-length=4-32
add action=discard chain=rfc1918 prefix=240.0.0.0/4 prefix-length=4-32
add action=discard chain=rfc1918 prefix=::/8 prefix-length=8-128
add action=discard chain=rfc1918 prefix=64:ff9b::/96 prefix-length=96-128
add action=discard chain=rfc1918 prefix=100::/8 prefix-length=8-128
add action=discard chain=rfc1918 prefix=200::/7 prefix-length=7-128
add action=discard chain=rfc1918 prefix=400::/6 prefix-length=6-128
add action=discard chain=rfc1918 prefix=800::/5 prefix-length=5-128
add action=discard chain=rfc1918 prefix=1000::/4 prefix-length=4-128
add action=discard chain=rfc1918 prefix=2001::/32 prefix-length=33-128
add action=discard chain=rfc1918 prefix=2001:2::/48 prefix-length=48-128
add action=discard chain=rfc1918 prefix=2001:3::/32 prefix-length=32-128
add action=discard chain=rfc1918 prefix=2001:10::/28 prefix-length=28-128
add action=discard chain=rfc1918 prefix=2001:20::/28 prefix-length=28-128
add action=discard chain=rfc1918 prefix=2001:db8::/32 prefix-length=32-128
add action=discard chain=rfc1918 prefix=2002::/16 prefix-length=17-128
add action=discard chain=rfc1918 prefix=3ffe::/16 prefix-length=16-128
add action=discard chain=rfc1918 prefix=4000::/3 prefix-length=3-128
add action=discard chain=rfc1918 prefix=5f00::/8 prefix-length=8-128
add action=discard chain=rfc1918 prefix=6000::/3 prefix-length=3-128
add action=discard chain=rfc1918 prefix=8000::/3 prefix-length=3-128
add action=discard chain=rfc1918 prefix=a000::/3 prefix-length=3-128
add action=discard chain=rfc1918 prefix=c000::/3 prefix-length=3-128
add action=discard chain=rfc1918 prefix=e000::/4 prefix-length=4-128
add action=discard chain=rfc1918 prefix=f000::/5 prefix-length=5-128
add action=discard chain=rfc1918 prefix=f800::/6 prefix-length=6-128
add action=discard chain=rfc1918 prefix=fc00::/7 prefix-length=7-128
add action=discard chain=rfc1918 prefix=fe80::/10 prefix-length=10-128
add action=discard chain=rfc1918 prefix=fec0::/10 prefix-length=10-128
add action=discard chain=rfc1918 prefix=ff00::/8 prefix-length=8-128