Configuring OTV on a Cisco ASR

During a project I’ve been working on, we needed to configure OTV on a Cisco ASR. I did write a blog for configuring OTV on a Nexus 7000 before (click here) but the configuration on a Cisco ASR router is a bit different. The used technologies and basic configuration steps are equal, but the syntax is different for a few configuration steps .
Unfortunately, the documentation is not as good as for the Nexus 7000. I’ve found one good configuration guide (here) but this guide isn’t covering all. So, it’s a good reason to write a blog post about the basic OTV configuration on a Cisco ASR router.
For more information about OTV, check this website.
First, the network layout for this OTV network.
OTV Network layout
 
As you can see in the diagram, the ASR routers are back-to-back connected. There is no guideline how to connect these routers, as long as there is IP connectivity between them with multicast capabilities and a MTU of atleast 1542 btyes.

OTV configuration on a ASR router REQUIRES you to have at least two physical interfaces. You cannot get OTV working with a one-interface configuration. Reason behind this is simple: the ASR is a router and is because of that unaware about VLANs. Also, the ‘trunk’ configuration on the ASR does not allow you to use subinterfaces.
– Step 1: Join interface configuration on both routers
DC1

interface TenGigabitEthernet0/1/0
 mtu 1542
 ip address 1.1.1.1 255.255.255.252
 ip pim passive
 ip igmp version 3
end

DC2

interface TenGigabitEthernet0/1/0
 mtu 1542
 ip address 1.1.1.2 255.255.255.252
 ip pim passive
 ip igmp version 3
end

The interface configuration is pretty basic. PIM and IGMP are used for multicast traffic for OTV. In our configuration, multicast is being used for MAC advertisements. Your WAN network has to be multicast enabled. Unicast-only is possible, you’ll need a adjacency server for that.
Another important configuration step is to change the MTU. OTV uses a header of 42 bytes, which means that the WAN network has to carry packets of at least 1542 bytes. Make sure your WAN network has a MTU of at least 1542 bytes!
– Step 2: Global configuration
DC1

otv site bridge-domain 11
otv site-identifier 0000.0000.0011

DC2

otv site bridge-domain 12
otv site-identifier 0000.0000.0012

The “Site bridge-domain” defines the site-VLAN. This VLAN is unique per-site and can not be stretched to other datacenters!
The site-identifier is a unique ID for a site (aka.. datacenter).
– Step 3: Overlay configuration
DC1

interface Overlay1
 no ip address
 otv control-group 239.2.3.4
 otv data-group 232.1.1.0/24
 otv join-interface TenGigabitEthernet0/1/0
 no otv suppress arp-nd
 service instance 10 ethernet
  encapsulation dot1q 10
  bridge-domain 10
 service instance 20 ethernet
  encapsulation dot1q 20
  bridge-domain 20
 service instance 30 ethernet
  encapsulation dot1q 30
  bridge-domain 30
 service instance 40 ethernet
  encapsulation dot1q 40
  bridge-domain 40
 service instance 50 ethernet
  encapsulation dot1q 50
  bridge-domain 50
 service instance 60 ethernet
  encapsulation dot1q 60
  bridge-domain 60

DC2

interface Overlay1
 no ip address
 otv control-group 239.2.3.4
 otv data-group 232.1.1.0/24
 otv join-interface TenGigabitEthernet0/1/0
 no otv suppress arp-nd
 service instance 10 ethernet
  encapsulation dot1q 10
  bridge-domain 10
 service instance 20 ethernet
  encapsulation dot1q 20
  bridge-domain 20
 service instance 30 ethernet
  encapsulation dot1q 30
  bridge-domain 30
 service instance 40 ethernet
  encapsulation dot1q 40
  bridge-domain 40
 service instance 50 ethernet
  encapsulation dot1q 50
  bridge-domain 50
 service instance 60 ethernet
  encapsulation dot1q 60
  bridge-domain 60

This is another configuration difference with the Nexus 7000: the service instance. With this configuration, the OTV enabled VLAN’s are defined. In our case, VLAN 10,20,30,40,50,60 are stretched between the datacenters.
– Step 4: Connection to datacenter LAN
DC1

interface TenGigabitEthernet0/2/0
 no ip address
 service instance 10 ethernet
  encapsulation dot1q 10
  bridge-domain 10
 service instance 11 ethernet
  encapsulation dot1q 11
  bridge-domain 11
 service instance 20 ethernet
  encapsulation dot1q 20
  bridge-domain 20
 service instance 30 ethernet
  encapsulation dot1q 30
  bridge-domain 30
 service instance 40 ethernet
  encapsulation dot1q 40
  bridge-domain 40
 service instance 50 ethernet
  encapsulation dot1q 50
  bridge-domain 50
 service instance 50 ethernet
  encapsulation dot1q 50
  bridge-domain 50

DC2

interface TenGigabitEthernet0/2/0
 no ip address
 service instance 10 ethernet
  encapsulation dot1q 10
  bridge-domain 10
 service instance 12 ethernet
  encapsulation dot1q 12
  bridge-domain 12
 service instance 20 ethernet
  encapsulation dot1q 20
  bridge-domain 20
 service instance 30 ethernet
  encapsulation dot1q 30
  bridge-domain 30
 service instance 40 ethernet
  encapsulation dot1q 40
  bridge-domain 40
 service instance 50 ethernet
  encapsulation dot1q 50
  bridge-domain 50
 service instance 50 ethernet
  encapsulation dot1q 50
  bridge-domain 50

As we know, the ASR is a router, so unaware of VLANs. The get a (required) layer 2 connection to the datacenter LAN, we need to configure service instances on the LAN facing interface. Note: you cannot share this interface with the WAN (join) interface!
This is the OTV configuration. It’s straight forward.
To verify the OTV configuration, use the following commands:
Show otv

Overlay Interface Overlay1
 VPN name                 : None
 VPN ID                   : 1
 State                    : UP
 AED Capable              : Yes
 IPv4 control group       : 239.2.3.4
 Mcast data group range(s): 232.1.1.0/23
 Join interface(s)        : TenGigabitEthernet0/1/0
 Join IPv4 address        : 1.1.1.1
 Tunnel interface(s)      : Tunnel0
 Encapsulation format     : GRE/IPv4
 Site Bridge-Domain       : 11
 Capability               : Multicast-reachable
 Is Adjacency Server      : No
 Adj Server Configured    : No
 Prim/Sec Adj Svr(s)      : None

Show otv route

Codes: BD - Bridge-Domain, AD - Admin-Distance,
       SI - Service Instance, * - Backup Route
OTV Unicast MAC Routing Table for Overlay1
 Inst VLAN BD     MAC Address    AD    Owner  Next Hops(s)
----------------------------------------------------------
 0    20   20     0050.56aa.217a 40    BD Eng Te0/2/0:SI99
 0    20   20     0050.56aa.38f1 40    BD Eng Te0/2/0:SI99
 0    20   20     0050.56aa.4fcb 40    BD Eng Te0/2/0:SI99
 0    20   20     0050.56ca.65df 40    BD Eng Te0/2/0:SI99
 0    20   20     0050.5b39.1533 40    BD Eng Te0/2/0:SI99
 0    20   20     00a0.8e42.1d49 40    BD Eng Te0/2/0:SI99
 0    20   20     c08c.6428.4b94 50    ISIS   hostname
 0    10   10    0010.daff.601b 40    BD Eng Te0/2/0:SI406

Show otv summary

OTV Configuration Information, Site Bridge-Domain: 11
Overlay VPN Name             Control Group   Data Group(s)      Join Interface   State
1       None                 239.2.3.4     232.1.1.0/23       Te0/1/0          UP
Total Overlay(s): 1

That’s it!

59 comments

  • The te0/2/0 connection to your DC LAN switch, is the switchport configured as a typical dot1q trunk with the allowed vlans? Also, would we need a seperate L3 link from ASR to DC switch for routed traffic that’s not part of the OTV vlans? For example, lets say vlan 500 is on the LAN switch at DC B with vlan 500 SVI, a packet from vlan 500 hits the SVI to get routed to the rest of the network at DC: A (the main data center) how does it get routed to the ASR so it can then get routed across the dark fiber link back to the other DC?

    • The switchport connected to Te0/2/0 is indeed a regular dot1q trunk with an allowed list.
      In the config I used for this blog, the ASR routers are back to back connected. All you need for connecting the ASR routers is a layer 3 connection. You can use (dark)fibers, mpls, some ISP layer 2 or 3 wan, as long as you have a connection with at least a mtu of 1542.
      If you use the same DC lan switch for the wan connection, make sure you don’t mix up internal and wan routing.

      • Hey Rob,
        I think Dan might have been asking about the link between ASRDC switch where the L3 termination point for all the local VLANs are, not necessarily between ASRs. So I actually have the same question: Te0/2/0, is that configured with an IP on one of the SIs or did you use a separate layer 3 link between your ASR and data center switch for routed traffic?
        Great article though.

        • Hi Ryan,
          Great question, you had me thinking for a few minutes!
          From configuration standpoint, it’s simply not possible to configure IP addresses on Service Instances (SIs). The ASR/OTV configuration does only extend your layer 2 domain between both DCs. If you need one or multiple routed connections, I’ll suggest you create a new VLAN on the switches in both DCs, extend the VLAN over OTV and use this VLAN as a transit network for your routed connections.

          • Great blog Rob.
            Currently working on the OTV implementation between two Data Center running 2 Dark Fiber VPL link. I am a bit confuse on the otv site bridge-domain and would really appreciate if you can clear up my confusion. In your example above are the “otv site bridge-domain 11” & “otv site bridge-domain 12” are these two vlans an active Vlans on both side of the Data center if not can Ijust use any VLANs that I don’t want to extend across between DataCenters? I know you mention not to extend these Vlans.

          • Hi Jepoy,
            There is only one site VLAN (bridge-domain) per-datacenter. You can use the same VLAN ID for both datacenters, but you really should not extend this VLAN. To make it more future proof (maybe someone is going to extent, by mistake, that specific VLAN in the future) I’ll recommend to use different VLAN IDs for each datacenter. The VLAN ID itself is your choice, it can be any regular VLAN ID.

          • Thanks Rob. So in essence I can just create a VLAN “500” on DC1 then VLAN “501” on DC2 and only use it for the purpose of (Bridge-domain) and not use these VLANS for anything else is that right?

          • Thanks for clarifying that. My other question if I may.
            1:) Client PC is talking to SQL server that’s on VLAN 20 and the SQL server presence is Local to (DC1). If we vmotion the SQL server to (DC2) and the VLAN 20 is extended between the DCs via OTV, how will the PC know to route the traffic over the OTV being that the LAN interface in your example doesn’t have a Layer 3 adjacency with the OTV router?

          • The laptop will never have knowledge about the vmotion: the MAC address of the VM will not change.
            After the vmotion, OTV will learn about the MAC address in DC2 (by a broadcast frame send from the VM) and it will update its OTV route table and advertise that specific MAC address to all other OTV devices.
            So in a few simple words: all cam tables in DC1 will point to the OTV device and OTV will extend the frame to the other datacenter.
            Because of the fact that OTV has to learn and advertise the movement of the MAC address, a vmotion between datacenters can result in a downtime of a few seconds. In real world implementations I’ve seen, that is less then 2 seconds in most cases.

          • Thank you Rob. Really appreciate your input and great blog.
            -Jepoy

  • Patrick Verougstraete

    Great start, thanks, but what pussels me..how would OTV and ASR be setup in a redundant way between 2 DC sites? 2 dark fibers, with each a ASR at both ends are the HW, but then the multicast domain is split in two? Any suggestions or alternatives? (Or where should I raise the case?)

    • I haven’t test that scenario, but in theory that should technically work. But, if 1 ASR router failes, you only have 1 dark fiber active. So, there is less redundancy if you use this scenario. A better scenario would be a routed WAN: get some routers (or switches) and create a routed WAN ring.

  • I have to extend a LAN switch that only contains VLAN 1/default VLAN. Is it possible for me to configure two interfaces on the ASR, one to connect to the switch with non-default VLANs, such as 500-510 and one to the switch that doesn’t have any VLAN configured?
    Thanks

    • That is possible to do! Configure the router port for the switch with the 500-510 vlans as dscribed in this blog. There are 2 options for the vlan1 switch:
      Configure a second router port on the ASR with the following config:
      Service instance 1 ethernet
      Encapsulation dot1q 1
      Bridge-domain 1
      And configure a trunk with a (dummy) native vlan on the vlan1 switch to connect to the ASR.
      Option 2:
      The ASR port config will be:
      Service instance 1
      Encapsulation native
      Bridge-domain 1
      Don’t forget to add this bridge domain in the overlay interface, regardless the option you choose.
      I would recommend to use option 1 with the dummy native vlan.

      • Thanks, I will give that a try.

      • I have the two ASRs and the two Cisco 3560G configured on both ends as you suggested. I am not able to ping across the two switches.
        Any thoughts?
        Thanks

        • Use “show otv” to check if the overlay is up.
          Can you see (at least) both mac addresses of your hosts in the “show otv route” table?
          Also, double check the trunk configuration of the switches and the otv routers!
          If you can’t get it running, please post the (partial) interface configs of the switches and routers to get a more clear view.

          • show otv
            Overlay Interface Overlay1
            VPN name : dp
            VPN ID : 1
            State : UP
            Fwd-capable : No
            Fwd-ready : No
            AED-Server : No
            Backup AED-Server : No
            AED Capable : No, overlay DIS not elected
            IPv4 control group : 239.2.3.4
            Mcast data group range(s): 232.1.1.0/24
            Join interface(s) : TenGigabitEthernet0/0/1
            Join IPv4 address : 172.31.2.1
            Tunnel interface(s) : Tunnel0
            Encapsulation format : GRE/IPv4
            Site Bridge-Domain : 101
            Capability : Multicast-reachable
            Is Adjacency Server : No
            Adj Server Configured : No
            Prim/Sec Adj Svr(s) : None
            DPASR#show run int g0/0/4
            interface GigabitEthernet0/0/4
            no ip address
            speed 1000
            no negotiation auto
            ntp disable
            cdp enable
            service instance 1 ethernet
            description Site VLAN – Not Extended
            encapsulation untagged
            bridge-domain 101
            !
            service instance 2 ethernet
            encapsulation dot1q 1
            bridge-domain 1
            DPASR#show run int ov1
            interface Overlay1
            no ip address
            otv control-group 239.2.3.4
            otv data-group 232.1.1.0/24
            otv join-interface TenGigabitEthernet0/0/1
            otv vpn-name dp
            no otv suppress arp-nd
            service instance 2 ethernet
            encapsulation dot1q 1
            bridge-domain 1
            !
            service instance 500 ethernet
            encapsulation dot1q 500
            bridge-domain 500
            !
            service instance 501 ethernet
            encapsulation dot1q 501
            bridge-domain 501
            !
            service instance 502 ethernet
            encapsulation dot1q 502
            bridge-domain 502
            !
            service instance 503 ethernet
            encapsulation dot1q 503
            bridge-domain 503
            !
            service instance 504 ethernet
            encapsulation dot1q 504
            bridge-domain 504
            !
            service instance 505 ethernet
            encapsulation dot1q 505
            bridge-domain 505
            !
            service instance 506 ethernet
            encapsulation dot1q 506
            bridge-domain 506
            !
            service instance 507 ethernet
            encapsulation dot1q 507
            bridge-domain 507
            !
            service instance 508 ethernet
            encapsulation dot1q 508
            bridge-domain 508
            !
            service instance 509 ethernet
            encapsulation dot1q 509
            bridge-domain 509
            DPASR#show otv vlan
            Key: SI – Service Instance, NA – Non AED, NFC – Not Forward Capable.
            Overlay 1 VLAN Configuration Information
            Inst VLAN BD Auth ED State Site If(s)
            0 1 1 – inactive Gi0/0/4:SI2
            0 500 500 – inactive(NFC) Gi0/0/5:SI500
            0 501 501 – inactive(NFC) Gi0/0/5:SI501
            0 502 502 – inactive(NFC) Gi0/0/5:SI502
            0 503 503 – inactive(NFC) Gi0/0/5:SI503
            0 504 504 – inactive(NFC) Gi0/0/5:SI504
            0 505 505 – inactive(NFC) Gi0/0/5:SI505
            0 506 506 – inactive(NFC) Gi0/0/5:SI506
            0 507 507 – inactive(NFC) Gi0/0/5:SI507
            0 508 508 – inactive(NFC) Gi0/0/5:SI508
            0 509 509 – inactive(NFC) Gi0/0/5:SI509
            Total VLAN(s): 11
            Note the VLAN is shown as inactive.
            Switch:
            show run int g0/1
            switchport trunk encapsulation dot1q
            switchport mode trunk
            switchport trunk allowed vlan 1
            switchport trunk native vlan 1
            Thank you.

          • I can suggest three things about the configuration:
            1)
            AED Capable : No, overlay DIS not elected
            This mostly means some multicast errors in the WAN. Are the routers back-to-back connected? Make sure multicast is configured in the WAN and on the join interface!
            2) the site vlan has the be tagged! It cannot be untagged on the inside interface (also, make sure this vlan is not in the overlay)
            3) on interface g0/0/4 service instance 2 you’ve configured vlan 1 as tagged, but the switch g0/1 is untagged for vlan 1.

          • 1. AED is now shown as Capable
            DPASR#show otv
            Overlay Interface Overlay1
            VPN name : dp
            VPN ID : 1
            State : UP
            Fwd-capable : Yes
            Fwd-ready : Yes
            AED-Server : Yes
            Backup AED-Server : No
            AED Capable : Yes
            IPv4 control group : 239.2.3.4
            Mcast data group range(s): 232.1.1.0/24
            Join interface(s) : TenGigabitEthernet0/0/1
            Join IPv4 address : 172.31.2.1
            Tunnel interface(s) : Tunnel0
            Encapsulation format : GRE/IPv4
            Site Bridge-Domain : 101
            Capability : Multicast-reachable
            Is Adjacency Server : No
            Adj Server Configured : No
            Prim/Sec Adj Svr(s) : None
            2. I have enabled tagging for site vlan
            service instance 1 ethernet
            description Site VLAN – Not Extended
            encapsulation dot1q 101
            bridge-domain 101
            3. I have remove switchport trunk native vlan 1 so it will be passed as tagged.
            When I do show otv vlan, I see VLAN 1 as active
            I am still not able to ping across the two switches.
            Thanks

          • Configure a dummy native vlan on the switchport. Cisco is using vlan 1 as a default native vlan. Configure something like:
            Swi trunk native vlan 99
            And check if you can see mac addresses in “show otv route”.

          • That is it. After creating a new VLAN on the 3560G and make that native VLAN, I am now able to ping across the OTV.
            Thanks

          • Another thing I am concerned with now is the HSRP groups on our routers that we are extending across this OTV. Does OTV do anything with HSRP or will it pass all the HSRP traffic?
            Thanks

          • OTV does filter all HSRP/VRRP/GLBP traffic. This is needed to achieve an active/active datacenter. Routing is always done in the local datacenter.

          • Now, when I do show otv, it is showing
            Overlay Interface Overlay1
            VPN name : dp
            VPN ID : 1
            State : DOWN(Cleanup in Progress)
            Reason : Admin Down
            Fwd-capable : No
            Fwd-ready : No
            AED-Server : No
            Backup AED-Server : No
            AED Capable : No, overlay DIS not elected
            IPv4 control group : 239.2.3.4
            Mcast data group range(s): 232.1.1.0/24
            Join interface(s) : TenGigabitEthernet0/0/1
            Join IPv4 address : 172.31.2.1
            Tunnel interface(s) : Tunnel0
            Encapsulation format : GRE/IPv4
            Site Bridge-Domain : 101
            Capability : Multicast-reachable
            Is Adjacency Server : No
            Adj Server Configured : No
            Prim/Sec Adj Svr(s) : None
            What does DOWN(Cleanup in progress) mean? It has been like that since yesterday.
            Thanks

          • I can only see: Reason : Admin Down. Did you shutdown the overlay1 interface?

          • On an ASR1001 FHRP/HSRP filtering does not function properly, not using the OTV’s built-in filtering, or even using an ACL and MAC filtering. The easiest workaround for this is to use HSRP authentication (You’re doing this anyway, right?!) and use a different MD5 or password for the pairs at each disparate site.

  • Hi,
    This is a great explanation…Do the gateways to the vlan’s reside on the downstream switch at each site? I will be using OTV to extend my Vlans between two DC’s across an MPLS network with other sites. If there are no IP addresses on the physical interface of the ASR connecting to the LAN, how do I route to the other sites out of the join interface through the MPLS network? Thanks.

    • Hi, there is no need to configure any routing on your internal network. The MAC address tables (with a little help of ARP) will take care of the layer 2 “routing” between your datacenters.

  • Hi
    Great Explanation, Best i’ve come across.
    Regarding the site VLAN, I have 2 ASR routers at a site connecting to my internal switches. So for both to see each other on the site, Will the following config do, considering I am using say vlan 50 for the site VLAN
    ASR config on both ASRs:
    otv site bridge-domain 50
    otv site-identifier 0000.0000.0050
    interface TenGigabitEthernet0/2/0
    no ip address
    service instance 50 ethernet
    encapsulation dot1q 50
    bridge-domain 50
    Then on the internal switches, create VLAN 50 and allow on the trunks to the OTV routers
    Thanks

    • Hi, Thanks!
      Your configuration is correct. Reminder: Do NOT stretch the site VLAN over the overlay to other datacenters!
      Also, your site identifier is 50, this could be any number and is not related to the bridge domain (aka site VLAN) as long as it is unique in your OTV network.

      • Thanks Rob
        Just to clarify, although the site identifier can be a unique number different from the bridge domain, do all edge devices on 1 site have to have the same site identifier and the same bridge domain. My guess is yes but just making sure.
        Is that also the case with the service instance number, is that just the instance number and not a vlan number, although in the example it is the same as the vlan number?
        Thanks

        • Hi,
          OTV on a stick setup? You really have to use two physical interfaces on the ASR to set up OTV.
          The control-group is the multicast address which is used for OTV control traffic over the WAN to the other datacenter(s). All OTV edge devices in the same overlay have to use the same control group IP.
          The data-group subnet is used for mapping multicast streams to a data group IP to be transported over OTV. Make sure this subnet has enough IPs for all your multicast streams.

          • Thanks, and yes i’m using two interfaces, one routed for the join interface and an internal interface

  • Hi
    Another questions…….The bridge domain (aka site vlan) for DC1 is 11 in the example. Should the bridge domain for all the service instances in DC1 not also be 11?
    Thanks

  • Hi Rob
    When extending a VLAN between two DCs, so for example vlan 10. Is a VLAN interface required at each DC on the local core switch, and how is this addressed in terms of IP addresses. Do they share a default gateway at each site somehow?
    Thanks

  • Hi,
    The OTV requires a multicast enabled transport network , I have queries regarding this.
    1) Does this restrict me to connect Data centers Over the Internet?
    2) What kind of connectivity should I get from Telecom Service Provider for connecting Data Centers. Is it MPLS L2 VPN Or MPLS Layer 3 VPN Or VPLS Or Dark Fiber Or Point To Point Link?
    3) Do I have to tell the Telecom Service Provider to enable Multicast on Internet or VPN?

    • Hi Ranjeet,
      It is not possible to implement OTV over internet for various reasons. The most important ones are multicast and a higher MTU of at least 1542.
      All your suggestions are working for OTV. As long as you have IP reachability with a MTU of 1542, you’re good to go. Multicast is not a requirement, if your service provider can’t enable it you can use OTV unicast mode (which uses a central “server” for helping with the MAC advertisements). The higher MTU is still a requirement.
      In my opinion: if multicast is available, use it.
      See my other blog post about multicast WAN for some more details: http://www.infraworld.eu/configure-multicast-wan-otv/

      • Hi Rob,
        Thanks for your reply , Appreciate it.
        What I make from your reply is that 1) You need a PC_CE- WAN link supporting MTU of 1542 2) Multicast is required only for NON-Unicast mode of OTV else it is required.
        I read that that OTV is an “Ethernet over MPLS over GRE tunnel” , How does Muiticast fit into this in Control and Data group? Why do we Multicast since it is complicating the Control/Data Plane?

        • Hi Ranjeet,
          The control-group multicast address is used to advertise the MAC addresses to other OTV edge devices. If you use unicast mode, this is not needed.
          The data-group multicast range is used to map internal multicast streams to a data-group IP, so the multicast stream is available in the other datacenters.
          OTV is indeed a EoMPLSoGRE protocol deepdown and multicast is used to find out where the GREs tunnels between the datacenters are needed. But this is out of your control, OTV is taking care of all this. The configuration in this post is all you need to get it running in multicast mode (which is recommended).

  • OTV is possible over the internet and does not require an MTU of 1542. On the ASR platform only, you can allow fragmentation for OTV. The Nexus family does not support this feature. In your topology, you would use the following global command:
    otv fragmentation join-interface TenGigabitEthernet0/1/0

  • Good evening; this configuration does not work; could you tell me what to do

  • Good evening; this configuration does not work; could you tell me what to do:

  • Rob – do you know of any reference material that lists the OTV capacity of the ASR1000 – specifcally the maximum number of VLANs supported? For example, the N7K has a maximum of 1500 OTV VLANs (assuming NX-OS 6.x or later) – is the ASR the same assuming the requisite IOS?

  • Hi Rob,
    I am procuring ASR1002 for OTV configuration and our core swicthes are 3850. As long as I can do VLAN it can communicate with edge router ASR to establish OTV?

    • Hi Nak,
      That is correct! You only need a trunk from your core switches to the ASR which is the OTV edge device. You can use any type of switch as core, as long as you can connect with a trunk.

  • Good Evening.
    First of all I want to thak you for the great config example. I need to build an OTV in unicast mode. There’s some differences in the design?

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