Problem with multiple BGP Sessions

[00utk43t7wMR1OMpb5d6]

Hey there I am trying to establish multiple eBGP Session with two different route servers in the same AS, I am able to establish one but the other want just would stay in Idle state. and the other one would come up online everytime I lose the first one, I think It might be just a licensing problem but I wanna make sure, Same thing happen for IPV6 

have Cisco IOS XE 16.07.01 and seck9 license

 BGP neighbor is 208.115.128.251, remote AS 24115, external link
BGP version 4, remote router ID 208.115.128.251
BGP state = Established, up for 15:55:47
Last read 00:00:00, last write 00:00:51, hold time is 180, keepalive interval is 60 seconds
Neighbor sessions:
1 active, is not multisession capable (disabled)
Neighbor capabilities:
Route refresh: advertised and received(new)
Four-octets ASN Capability: advertised and received
Address family IPv4 Unicast: advertised and received
Graceful Restart Capability: advertised and received
Remote Restart timer is 120 seconds
Address families advertised by peer:
none
Long-lived Graceful Restart Capability:
Enhanced Refresh Capability: advertised and received
Multisession Capability:
Stateful switchover support enabled: NO for session 1
Message statistics:
InQ depth is 0
OutQ depth is 0

[Giuseppe Larosa]

Hello @00utk43t7wMR1OMpb5d6 ,

post

show version

and

show run | begin router bgp

and

show ip bgp summary

A license issue should make BGP not usable , up to now I have never seen a limitation in the number of BGP peers.

Are using eBGP wilth loopbacks ?

Have you configured in that case ebgp multihop and host static routes ponting to the correct next-hop ?

There is a chance that packets for second session are sent to the first established peer using a default route learned in eBGP  for example.

Hope to help

Giuseppe

[00utk43t7wMR1OMpb5d6]

Cisco IOS XE Software, Version 16.07.01
Cisco IOS Software [Fuji], ISR Software (X86_64_LINUX_IOSD-UNIVERSALK9-M), Version 16.7.1, RELEASE SOFTWARE (fc6)
ROM: IOS-XE ROMMON

ixp-ap-4321 uptime is 5 weeks, 4 days, 23 hours, 52 minutes
Uptime for this control processor is 5 weeks, 4 days, 23 hours, 54 minutes
System returned to ROM by Reload Command
System image file is "bootflash:isr4300-universalk9.16.07.01.SPA.bin"
Last reload reason: Reload Command

This product contains cryptographic features and is subject to United
States and local country laws governing import, export, transfer and
use. Delivery of Cisco cryptographic products does not imply
third-party authority to import, export, distribute or use encryption.
Importers, exporters, distributors and users are responsible for
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agree to comply with applicable laws and regulations. If you are unable
to comply with U.S. and local laws, return this product immediately.

A summary of U.S. laws governing Cisco cryptographic products may be found at:
http://www.cisco.com/wwl/export/crypto/tool/stqrg.html

If you require further assistance please contact us by sending email to
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Suite License Information for Module:'esg'

--------------------------------------------------------------------------------
Suite Suite Current Type Suite Next reboot
--------------------------------------------------------------------------------
FoundationSuiteK9 None None None
securityk9
appxk9

AdvUCSuiteK9 AdvUCSuiteK9 Permanent AdvUCSuiteK9
uck9
cme-srst
cube

Technology Package License Information:

-----------------------------------------------------------------
Technology Technology-package Technology-package
Current Type Next reboot
------------------------------------------------------------------
appxk9 None None None
uck9 None None uck9
securityk9 None None None
ipbase ipbasek9 Permanent ipbasek9

cisco ISR4321/K9 (1RU) processor with 1793357K/6147K bytes of memory.
Processor board ID FLM2231V00S
2 Gigabit Ethernet interfaces
32768K bytes of non-volatile configuration memory.
4194304K bytes of physical memory.
3125247K bytes of flash memory at bootflash:.
0K bytes of WebUI ODM Files at webui:.

Configuration register is 0x2102

router bgp 264836
no bgp enforce-first-as
bgp log-neighbor-changes
bgp graceful-restart
neighbor 2001:504:0:10:0:2:4115:1 remote-as 24115
neighbor 2001:504:0:10:0:2:4115:2 remote-as 24115
neighbor 208.115.128.251 remote-as 24115
neighbor 208.115.128.252 remote-as 24115
!
address-family ipv4
no neighbor 2001:504:0:10:0:2:4115:1 activate
no neighbor 2001:504:0:10:0:2:4115:2 activate
neighbor 208.115.128.251 activate
neighbor 208.115.128.252 activate
exit-address-family
!
address-family ipv6
neighbor 2001:504:0:10:0:2:4115:1 activate
neighbor 2001:504:0:10:0:2:4115:2 activate
exit-address-family
!
ip forward-protocol nd
ip http server

BGP router identifier 208.115.128.34, local AS number 264836
BGP table version is 731046, main routing table version 731046
92874 network entries using 23032752 bytes of memory
92874 path entries using 12630864 bytes of memory
18314/18286 BGP path/bestpath attribute entries using 5127920 bytes of memory
23904 BGP AS-PATH entries using 1147828 bytes of memory
150 BGP community entries using 8064 bytes of memory
12 BGP extended community entries using 416 bytes of memory
0 BGP route-map cache entries using 0 bytes of memory
0 BGP filter-list cache entries using 0 bytes of memory
BGP using 41947844 total bytes of memory
BGP activity 754224/617811 prefixes, 10297227/10160823 paths, scan interval 60 secs

Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
208.115.128.251 4 24115 49812 144229 731015 0 0 16:17:23 92874
208.115.128.252 4 24115 0 0 1 0 0 00:04:43 Idle

I am attaching the 3 outputs of the comands and I am not using loopbacks, I have not configure ebgp multihop, I do have conmunication to those route servers that I am trying to establish the sessions with, and I can establish them by separetly but not at the same time

there is an another detail, the session that is in Idle state keep reseting all the time

[Giuseppe Larosa]

Hello @00utk43t7wMR1OMpb5d6 ,

if you have direct eBGP sessions with both peers there is no routing issue or ebgp multhop need.

I would contact your ISP AS 24115 to ask if they have configured the eBGP session on  their side on device with IP 208.115.128.252 .

if you configure

neighbor 208.115.128.251 shutdown

what happens does the other eBGP peer  becomes established ?

>> I can establish them by separetly but not at the same time

Again it is your ISP that is giving you a service with an active eBGP peer + a cold backup.

Warning : do this test in a declared maintenance window. In any case it may be caused by the ISP.

final note:

check with show ip arp what MAC addresses are associated to the two IP addresses 208.115.128.251 and 208.115.128.252 they should be different.

Hope to help

Giuseppe

[Harold Ritter]

Hi @00utk43t7wMR1OMpb5d6 ,

Can you check the logs to see if there is any message indicating why the second session keeps flapping.

Regards,

[MHM Cisco World]

dual eBGP Peer, Are you using loopback and default route to connect two eBGP Peers?

if this case then 
add only static route for loopback toward each interface for each eBGP.

[MHM Cisco World]

208.115.128.251 <- this is ISP peer ip what is mask here ? 
also other ip address what is mask ? are you sure this ip of ISP or it the Network IP ?