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BGP routing table entry fields meaning

TinyMiny
Level 1
Level 1

Hi all,

 

I found a Cisco Live Presentation with a BGP routing table entry, see image attached.

And I have a question regarding this BGP routing table entry:

 

In the Line:

BGP routing table entry for [2]:[0]:[15335345]:[48]:[0050.56a8.b003]:[0]:[0.0.0.0]/216, 

 

What does all of these mean? I think it's the following:

 

[2] = BGP EVPN Prefix Type

[0] = Segment Type (What is a segment type?)

[15335345] = Ethernet Tag ID 

[48] = MAC Address Length

[0050.56a8.b003] = MAC address

[0] = IP address Length

[0.0.0.0] IP address

/216 = What is this?

Is this correct?

 

And how would it look like if we have a L3 packet? Then these fields would be empty or not:

[15335345] = Ethernet Tag ID 

[48] = MAC Address Length

[0050.56a8.b003] = MAC address

 

 

Then below there is also the following line:

 

192.168.1.254 (metric 3) from 192.168.1.101 (192.168.1.101)

 

192.168.1.254 = Next Hop (Dataplane TEP/ETEP in ACI)

192.168.1.101 is the BGP Address of the sending Switch (ACI Spine)

 

Is this correct or wrong?

 

Thank you all.

 

 

 

 

 

 

 

 

 

2 Replies 2

Giuseppe Larosa
Hall of Fame
Hall of Fame

Hello @TinyMiny ,

it would be helpful to provide context if you could add a link to the presentation and the page.

 

I try to answer to some of your questions using only the image you have provided

/216   this is simply the total number of bits in the MP NLRI used by EVPN.

 

For the rest to be noted the image says that

There is an RD of 1:16777199   route distinguisher and there is an RT extended community RT:5:16

The prefix is accepted based on the RT value.

 

it is an iBGP learned advertisement as the AS path attribute is NONE  = empty.

the IGP metric of 3 is the metric to the prefix originator node with IP 192.168.1.254   via 192.168.1.101.

 

>> [15335345] = Ethernet Tag ID  this can be true but it is considered a label in the image.

 

For your further questions I think it is enough to go on in the presentation to see how it changes if there is an IP prefix to advertise within the EVPN.

 

Hope to help

Giuseppe

 

this is VXLAN EVPN and 0.0.0.0/216 is represent the IPV4 and this router is origin of this MAC-address.

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