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Hello,<br>
<br>
We use BIRD as route server with the well-known "BGP Community
policy based filtering" as in most of all other IXP with the
following type:<br>
<ul>
<li><i>Do not announce a prefix to a certain peer: 0:peer-as</i></li>
<li><i>Announce a prefix to a certain peer: IXP_AS:peer-as</i></li>
<li><i>Do not announce a prefix to any peer: 0:IXP_AS</i></li>
<li><i>Announce a prefix to all peers: IXP_AS:IXP_AS</i></li>
</ul>
But recently we came across the following case:<br>
<br>
A member of our IXP is sending his prefixes with attached a huge
count of BGP communities ( ~ 750 pcs ) <br>
<br>
Each of the attached community has following type: 0:ASN ( peer-as
).<br>
<br>
We see that BIRD accepts these prefixes from member but it return
the following error notification:<br>
<br>
2016-06-30 10:06:59 <ERR> R0_248: Attribute list too long,
skipping corresponding routes<br>
2016-06-30 10:06:59 <ERR> R0_248: - route <b>x.x.x.0/24</b>
skipped <br>
<br>
In the same time I'm able to see the prefixes that are exported fine
to all member RIBs<font color="#ff0000"> <font color="#000000">(for
which there is no prohibiting with 0:ASN) via pipes<br>
but in spite of that , the prefix is not advertised to any peer
over eBGP protocol.</font></font><br>
<br>
In addition at the same time I'm able to see that the prefixes
persist into the RIB and BIRD shows that they're advertised but
obviously this is not a true.<br>
<br>
Here is the output with a brief explanation of our scenario:<b><br>
<br>
</b>R0_248<b> </b>- protocol BGP of member that should accept the
prefixes <br>
R0_132 - protocol BGP of the member that sends the prefixes with the
huge count of communities.<br>
10.0.0.132 - the peer from protocol R0_132<br>
T60230 - connected table to R0_248<br>
Prefix: <b>x.x.x.0/24</b> - prefix with ~750 communities.<br>
<br>
<i> # birdc "show route export R0_248 </i><i><b>x.x.x.0/24</b></i><i>
all"</i><br>
<b>x.x.x.0/24</b> via 10.0.0.132 on eth0 [R0_132 10:01:33] *
(100) [ASxxxxi]<br>
Type: BGP unicast univ<br>
BGP.origin: IGP<br>
<i>BGP.as_path: yyyy xxxx</i><br>
BGP.next_hop: 10.0.0.132<br>
BGP.med: 1000<br>
BGP.local_pref: 100<br>
BGP.community: (64700,44217) (1,1082) (65400,65400) (65400,0)
(0,42) (0,251) (0,286) (0,553) (0,680) (0,702) (0,714) (0,1239)
(0,1241) (0,1248) (0,1267) (0,1273) (0,1547) (0,1668) (0,1680)
(0,1764) (0,2119) (0,2484) (0,2603) (0,2613) (0,2635) (0,2686)
(0,2818) (0,2828) (0,2854) (0,2857) (0,2906) (0,2914) (0,3209)
(0,3216) (0,3223) (0,3225) (0,3252) (0,3255) (0,3257) (0,3292)
(0,3303) (0,3320) (0,3327) (0,3356) (0,3491) (0,3549) (0,3561)
(0,3741) (0,3786) (0,3856) (0,3910) (0,4134)<br>
......................................................................<br>
......................................................................<br>
......................................................................<br>
(0,4589) (0,4637) (0,4651) (0,4657) (0,4766) (0,4788)
(0,4809) (0,5089) (0,5391) (0,5400) (0,5404) (0,5409) (0,5410)
(0,5413) (0,5430) (0,5466) (0,5483) (0,5539) (0,5563) (0,5578)
(0,5588) (0,5603) (0,5605) (0,5713) (0,6083) <br>
(0,60280) (0,60294) (0,60404) (0,60447) (0,60764) (0,60868)
(0,61186) (0,61244) (0,61266) (0,61317) (0,61438) (0,61955)
(0,62023) (0,62044) (0,62093) (0,62325) (0,62336) (0,62363)
(0,62955) (0,63199) (0,63311) (0,63949) (0,64597) (44217,1039)
(44217,1049) (44217,1053) (44217,1064) (44217,1074) (44217,9101)<br>
<br>
# birdc "show route table T60230 <i><b>x.x.x.0/24</b></i>"<br>
<i><b>x.x.x.0/24</b></i> via 10.0.0.132 on eth0 [R0_132
10:01:33] * (100) [ASxxxxi]<br>
<br>
Our BIRD version is 1.4.5 We have tried with the latest 1.6.0 but
there is no effect. <br>
<br>
Furthermore during our troubleshooting as a separate issue we have
observed that we can't add more than ~505 communities to a given
prefix.<br>
<br>
I hope this information will be useful for resolving this issue.<br>
<br>
Any ideas or thoughts are highly appreciated!<br>
<br>
Thanks in advance!<br>
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<h2 style="color: #008081; font-weight: 700; font-size: 14px;
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<h4 style="color: #88CDD3; font-weight: 100; font-size: 14px;
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