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- About d.wingert
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Member since
09-15-2005
65
Posts
7
Helpful
2
Solutions
Created by
d.wingert
in Other Data Center Subjects
in Other Data Center Subjects
04-19-2018
07:33 PM
04-19-2018
07:33 PM
Many many thanks to Vinit Jain!
Here's what I did:
Copied the (non-compacted) "nxos.7.0.3.I7.3.bin" from usb1: to bootflash: and named the file "wheelie.bin"
Then I did a "copy scp:wheelie.bin bootflash:nxos.7.0.3.I7.3.bin compact vrf management" and used the switch's local IP on the mgmt 0 interface as the source IP (maybe you can also use the IP of a local loopback interface)
Afterwards "install all nxos bootflash:nxos.7.0.3.I7.3.bin" to complete the upgrade
... View more
09-14-2016
07:34 AM
Hello Joseph,
Yes all four routers in the topology support it and I tried it on R1 and its neighbors: R2 and R4.
IOS on the devices: c2800nm-adventerprisek9-mz.151-4.M7
Thanks,
Dirk
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Hi Paul,
I will revisit the scenario and will report back.(soft resets on R1 and its peers without the "bgp always-compare-med" had no effect)
My main interest though is in which timer is at play here, possible that this can only be answered by a Cisco employee familiar with the inner workings of the IOS as I haven't been able to find any BGP related timer with a default value of 30 minutes/1800 seconds so far.
It might even be IOS version dependent. (will explore that as well)
Thanks,
Dirk
... View more
Hi Milan,
Yes, 'show ip bgp' continued to show the paths with the MED of ' 4294967295' as the best until the 30 minutes passed.
Soft clears (in and out) on R1 as well as it's peers (R2 and R4) didn't have any effect.
Only a hard reset via "clear ip bgp *" causes R1 to choose paths with a lower MED after the peerings re-established.
Thanks,
Dirk
... View more
09-13-2016
01:25 PM
Hello Everyone,
Observation: After applying the cmd 'bgp bestpath med missing-as-worst' on a router which already has "bgp bestpath as-path ignore" configured, a 'show ip bgp' shows prefixes which didn't have a MED assigned previously with a new value of "4294967295" - which is what I expected to see.
What I didn't expect was that the router continued to use the paths with the MED value of " 4294967295" for a full 30 minutes before changing to paths which had lower MED values.
Q: Any idea which timer within BGP is responsible for this behavior?
This is in a lab environment which physical hardware, running c2800nm-adventerprisek9-mz.151-4.M7
Only routing protocol used was eBGP with each router peering only with its directly connected neighbors:
R1 (AS100) - R2 (AS200)
| |
R4 (AS400) - R3 (AS300)
Each router only advertises a single /8 prefix into BGP (i.e. R1= 1.0.0.0/8, R2= 2.0.0.0/8 , R3= 3.0.0.0/8, R4= 4.0.0.0/8)
R1 has ' bgp bestpath med missing-as-worst' & 'bgp bestpath as-path ignore' configured.
R4 has an out-going route-map pointing at R1 which sets the MED to 100 for all prefixes
R2 doesn't modify any attributes so the prefixes 3.0.0.0/8 and 4.0.0.0/8 will show up on R1 with the MED value of ' 4294967295' once ' bgp bestpath med missing-as-worst' is applied to R1
No changes where where performed during the 30 minutes, R1 just dynamically changed to the paths with the lower MED values after 30 minutes.
Thanks for your help!
Dirk.
... View more
- Tags:
- ## BGP
Labels:
11-13-2015
11:31 AM
Hello Everyone,
Is there a command available on a 4948 which allows to verify if marked traffic (DSCP) is received on a port?
Thanks
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Labels:
04-16-2013
03:41 PM
Hello Everyone, I am having issues with my floating static route - this must be something easy but I am not "seeing" it today... :-) I have a few hundred prefixes from the 10.0.0.0/12 range in my BGP table and I want to be able to advertise another range (192.168.1.0/27) when any element of the 10.0.0.0/12 aggregate is present in the routing table. Example: If 10.1.1.1/32 is present, then advertise 192.168.1.0/27. My current problem is that the floating static doesn't kick in, even when the locally originated aggregate is present. Looks like the floating static doesn't like following another static route that is pointing to Null0 (which gets dynamically originated by the aggregate). Currently the floating static only kicks in when a prefix is present in the routing table that has zeros in all of the last three octets, i.e. 10.0.0.0/12 , 10.0.0.0/16 , 10.0.0.0/32 Any solutions / ideas to get around this? ! ip route 192.168.1.0 255.255.255.224 10.0.0.0 ! router bgp 65000 aggregate-address 10.0.0.0 255.240.0.0 network 192.168.1.0 mask 255.255.255.224 ! CE1#sh ip route 10.0.0.0 255.240.0.0 Routing entry for 10.0.0.0/12 Known via "bgp 65000", distance 200, metric 0, type locally generated Routing Descriptor Blocks: * directly connected, via Null0 Route metric is 0, traffic share count is 1 AS Hops 0 Thanks, Dirk
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Labels:
02-11-2009
08:00 AM
Hello there, Is there a configuration option (similar to "no keepalive" on a copper port) to force a GigabitEthernet Fibre port to come up? I am working on a 7304-NSE150 with fibre GBICs plugged into the ports on the NSE. I tried a "no keepalive" and "no negotiation auto" but without any luck. Any ideas? Regards, Dirk
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Labels:
02-23-2008
06:10 AM
Hello Shivlu, Thank you very much for your reply, it's the right approach - it's just missing the range from 64512-64599. I found this here: ip as-path access-list 150 permit _(6451[2-9]|645[2-9][0-9]|64[6-9][0-9][0-9])_ ip as-path access-list 150 permit _(65[0-4][0-9][0-9]|655[0-2][0-9]|6553[0-5])_ on http://www.merit.edu/mail.archives/nanog/2003-01/msg00365.html Kind regards, Dirk
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02-22-2008
12:36 PM
Hello everybody, I want to filter all prefixes that have private ASNs in their AS path and I want to achive this via an ip as-path access-list. (neighbor x.x.x.x remove-private-as isn't an option) What would a regexp have to look like that filters all ASNs from 64512-65535 ? Regards, Dirk
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Labels:
02-11-2008
04:11 AM
Hello David, It does indeed! Thank you very much! Now to my next question :-) Why does a pretty recent IOS like c3640-jk9o3s-mz.123-14.T7.bin still have the advertisement of these frames as a default? Considering things like security and running extra processes etc; shouldn't stuff like this be removed from the default behaviour of the IOS? Regards, Dirk
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02-05-2008
02:53 PM
Hello everybody, Can somebody shed any light on this? Or even know who to alter this behaviour(filter, disable, etc)? I have a capture running on an ethernet interface of a 3640 with IOS c3640-jk9o3s-mz.123-14.T7.bin CDP and keepalives are disabled, no routing, no ip addresses configured. Still Wireshark shows me that the interface is sending frames with a protocol id of 0x6002 (DEC DNA Remote Console) around every 515 to 705 seconds. What are these frames for? Regards, Dirk
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Labels:
10-08-2007
07:34 AM
Thank you both for your helpful replies! Ankur: It's more a matter of interest than need. As I understand the Bridge ID is derived from the base MAC address of a switch. I was working on a lab scenario were I wanted to alter the choice of root bridge without making changes to any of the spanning-tree parameters. Cheers, Dirk
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10-02-2007
01:42 AM
Hello there, I would just like to know if it is possible to change the Base Ethernet MAC address on a Cat 3750 and if so, how? Regards, Dirk
... View more
Labels:
Created by
d.wingert
in Other Data Center Subjects
04-19-2018
04-19-2018
Many many thanks to Vinit Jain! Here's what I did: Copied the
(non-compacted) "nxos.7.0.3.I7.3.bin" ...
09-14-2016
Hello Joseph, Yes all four routers in the topology support it and I
tried it on R1 and its neighbors...
09-13-2016
Hello Everyone, Observation: After applying the cmd 'bgp bestpath med
missing-as-worst' on a router ...
11-13-2015
Hello Everyone, Is there a command available on a 4948 which allows to
verify if marked traffic (DSC...
04-16-2013
Hello Everyone,I am having issues with my floating static route - this
must be something easy but I ...
02-11-2009
Hello there,Is there a configuration option (similar to "no keepalive"
on a copper port) to force a ...
02-23-2008
Hello Shivlu,Thank you very much for your reply, it's the right approach
- it's just missing the ran...
02-22-2008
Hello everybody,I want to filter all prefixes that have private ASNs in
their AS path and I want to ...
02-11-2008
Hello David,It does indeed! Thank you very much!Now to my next question
:-)Why does a pretty recent ...
02-05-2008
Hello everybody,Can somebody shed any light on this? Or even know who to
alter this behaviour(filter...
10-08-2007
Thank you both for your helpful replies!Ankur: It's more a matter of
interest than need. As I unders...
Public Statistics
| Date Registered | 09-15-2005 11:15 PM |
| Date Last Visited | 06-20-2018 03:53 PM |
| Total Messages Posted | 65 |
| Total Helpful Votes Received | 7 |
