Configuration advice

[Tareq Emad Al Asfoor]

Dear , I have 

- (2) Switch 3850 

- (1) NCS 540 

- (4) Server 

As shown in the attachment, any one can advice me how i can config this topology in the NCS 450 as below 

- Port between the NCS and SW-1 port trunk on VLAN 100 

- Port between the NCS and SW-2 port trunk on VLAN 100 

- Port between the NCS and Server-1 port access on VLAN 50

- Port between the NCS and Server-2 port access on VLAN 50

and the IP address on the NCS

interface BVI 100

10.10.10.1/24

interface BVI 50

10.10.20.1/24

Kind Regards, 

[Giuseppe Larosa · Accepted solution]

Hello Tareq,

the NCS 540 is based on IOS XR and its configuration is quite different from that of an IOS XE switch like C3850.

In the NCS 540 you need to configure IRB = Integrated routing and bridging.

You need to configure two bridge domains one for Vlan 50 and one for Vlan 100.

Follow the document below

https://www.cisco.com/c/en/us/td/docs/iosxr/ncs5xx/interfaces/66x/b-interfaces-hardware-component-cg-66x-ncs540/cg_65_integrated_routing_and_bridging.html#ID-1763-000003f9

First of all, after configuration changes to make them effective you need to commit issuing the commit command.

IOS XR configuration is hierarchical.

a) create the configuration of the two BVI interfaces

configure

interface bvi 50

ipv4 address 10.10.20.1 255.255.255.0

no shut

exit

interface bvi 100

ipv4 address 10.10.10.1 255.255.255.0

no shut

exit

commit

b) configure the bridge groups, bridge domains and access links for each BG/BD

configure

! associate access interfaces to L2transport services

interface gi0/0/0/1 l2transport

description to server 1

exit

interface gi0/0/0/2 l2transport

description to server 2

exit

! enter L2VPN configuration section

l2vpn

bridge group BG-Vlan50

bridge-domain BD-Vlan50

! associates the access interfaces to servers to the bridge-domain

interface gi0/0/0/1

interface gi0/0/0/2

commit

! associate BVI 50 interface to the bridge domain

configure

l2vpn

bridge group BG-Vlan50

bridge-domain BD-Vlan50

routed-interface bvi 50

commit

For the interfaces to the two Catalyst 3850 you need to associated tagged subinterfaces to the second bridge group.

configure

interface gi0/0/0/3.100 l2transport

encapsulation dot1q 100

desc to switch1

exit

interface gi0/0/0/4.100 l2transport

encapsulation dot1q 100

desc to switch 2

exit

l2vpn

bridge group BG-Vlan100

bridge-domain BD-Vlan100

! here we refer to the tagged subinterfaces as access links

interface gi0/0/0/3.100

interface gi0/0/0/4.100

routed-interface bvi 100

commit

Note: interfaces BVI 50 and BVI 100 need to be created before and committed before the above changes are done.

The physical interfaces to the switches do not need any configuration the tagged subinterfaces are configured only as explained above.

Hope to help

Giuseppe

[Tareq Emad Al Asfoor]

Thanks :) 

[Giuseppe Larosa · Accepted solution]

Hello Tariq,

check the status of the BVI interface with

show interface BVI 100

if it is up/up you should be able to ping.

Verify the ARP entries for the servers using

show arp 10.10.10.10

show arp 10.10.10.20

Hope to help

Giuseppe

[Tareq Emad Al Asfoor]

Solved ..Many Thanks ..