IGP - BGP aggregation problems 3.30

RouterOS Forwarding Protocols
1

We want to try new IGP routes aggregation in BGP, but with no success. If we look at “/routing bgp advertisements print” routes are agregated OK here (only 3x /24 per peer). But on peering routers there are ALL routes … both agregates and original … (about 250x /32 + 1x /27 + 3x /24)

Our configuration is:

/routing bgp instance
set default as=65408 client-to-client-reflection=no comment="" disabled=no ignore-as-path-len=no name=default out-filter=bgp-networks redistribute-connected=yes redistribute-ospf=yes redistribute-other-bgp=no redistribute-rip=no redistribute-static=yes router-id=\
    10.0.18.8
/routing bgp aggregate
add advertise-filter="" attribute-filter="" comment="" disabled=no include-igp=yes inherit-attributes=yes instance=default prefix=172.30.1.0/24 summary-only=yes suppress-filter=""
add advertise-filter="" attribute-filter="" comment="" disabled=no include-igp=yes inherit-attributes=yes instance=default prefix=172.30.101.0/24 summary-only=yes suppress-filter=""
add advertise-filter="" attribute-filter="" comment="" disabled=no include-igp=yes inherit-attributes=yes instance=default prefix=172.30.2.0/24 summary-only=yes suppress-filter=""
/routing bgp peer
add address-families=ip comment="" default-originate=if-installed disabled=no hold-time=3m in-filter="" instance=default multihop=no name=roudnice-esus nexthop-choice=force-self out-filter=to-esus remote-address=XXX remote-as=65400 remove-private-as=no \
    route-reflect=no tcp-md5-key="" ttl=255
add address-families=ip comment="" default-originate=if-installed disabled=no hold-time=3m in-filter="" instance=default multihop=no name=benecko-lugos nexthop-choice=force-self out-filter=to-benecko remote-address=XXX remote-as=65424 remove-private-as=no \
    route-reflect=no tcp-md5-key="" ttl=255
add address-families=ip comment="" default-originate=if-installed disabled=no hold-time=3m in-filter=from-tamesis instance=default multihop=no name=bratrouchov-tamesis nexthop-choice=force-self out-filter=to-tamesis remote-address=XXX remote-as=65432 \
    remove-private-as=no route-reflect=no tcp-md5-key="" ttl=255

Is it some BUG or bad configuration ?

Thank you

2

since ‘summary-only=yes’ - seems like a bug… as a workaround, you may use out-filter to filter masks with length 25-32

3

Im seeing the same thing on 3.28. I tried using an out filter and aggregation and it drops the entire network, the aggregate is not being advertised.

4

in v3.28, for aggregation to be advertised, you need to have an aggregated route in routing table. either add it statically (with type ‘unreachable’), or upgrade to v3.30 - where ‘Synchronize’ option was returned back to ‘Networks’ again and should solve your problem.

if not - please post your aggregation and filtering rules

5

Thanks for the tip I will give it a whirl. I found very little documentation and only some really old posts about route aggregation. Even the wiki was lacking any real detail.

6

You were spot on. With 3.28 I entered a dummy route unreachable for the /22 and filtered the /32’s out and it worked fine.

On 3.30:
I used a filter to discard the /32’s advertised then used BGP NETWORKS and synchronize setting to push the aggregate out without the dummy route. Thanks for the tips!

steve

7

are /32 routes still advertised in 3.30 w/o filtering and with ‘summary-only=yes’?

8

Yep, need filters, that is unless I configured it wrong.

Router C
[admin@RouterC] /routing bgp network> pr
Flags: X - disabled, A - active

NETWORK SYNCHRONIZE

0 A 208.91.8.0/22 yes

[admin@RouterC] /routing bgp aggregate> pr
Flags: X - disabled
0 instance=default prefix=208.91.8.0/22 summary-only=yes
inherit-attributes=yes attribute-filter=“” suppress-filter=“”
advertise-filter=“”

Router B
[admin@RouterB] /ip route> pr
Flags: X - disabled, A - active, D - dynamic,
C - connect, S - static, r - rip, b - bgp, o - ospf, m - mme,
B - blackhole, U - unreachable, P - prohibit

DST-ADDRESS PREF-SRC G GATEWAY DISTANCE IN..

4 ADC 10.9.9.2/32 10.9.9.2 0 lo..
5 A S 10.9.9.3/32 r 10.2.2.3 1 et..
6 A S 10.9.9.4/32 r 10.2.2.3 1 et..
9 ADb 208.91.8.0/22 r 10.9.9.3 200 et..
[admin@RouterB] /ip route>

The aggregate is there but so are the /32’s…