IP Infusion: EVPN-MPLS first look on GA 6.0

IP Infusion just released OcNOS version 6.0 and the release notes, as well as press release, show a focus on EVPN with an MPLS data plane. Don’t forget EVPN and VxLAN aren’t mutually exclusive, EVPN runs on and was originally designed for a MPLS data plane. I recently discussed this on a podcast EVPN doesn’t need VxLAN if you want to know more on that topic.

Lets take a look at basic EVPN-VPWS and EVPN-VPLS deployment. Since we’re looking at an MPLS data plane we will utilize ISIS-SR for MPLS. We’re utilizing ISIS-SR as it is increasingly replacing LDP and RSVP-TE for label distribution.

IGP and Label Distribution

First let’s look at the IGP setup and label distribution as everything else will be built on top of this.

ipi-1.lab.jan1.us.ipa.net#show run int lo
interface lo
 ip address
 ip address secondary
 ipv6 address ::1/128
 ipv6 address 2001:db8::1/128
 prefix-sid index 101
 ip router isis UNDERLAY
 ipv6 router isis UNDERLAY

We have to set an index to create the node-sid for this device. In this case we use 101.

ipi-1.lab.jan1.us.ipa.net#show run segment-routing
 mpls sr-prefer
 global block 16000 23999

Since our segment routing global block starts at 16000 the node-sid becomes 16101 as the index + the start of the SRGB defines the sid. Additionally, we run mpls sr-prefer as this will prefer SR labels over LDP or RSVP-TE labels.

ipi-1.lab.jan1.us.ipa.net#show run isis
router isis UNDERLAY
 is-type level-1-2
 metric-style wide
 mpls traffic-eng router-id
 mpls traffic-eng level-1
 mpls traffic-eng level-2
 capability cspf
 fast-reroute ti-lfa level-1 proto ipv4
 fast-reroute ti-lfa level-2 proto ipv4
 net 49.0015.1001.2700.0001.00
 segment-routing mpls

Finally, we have to enable ISIS for segment routing.

ipi-1.lab.jan1.us.ipa.net#show clns neighbors

Total number of L1 adjacencies: 1
Total number of L2 adjacencies: 1
Total number of adjacencies: 2
Tag UNDERLAY:  VRF : default
System Id      Interface   SNPA                State  Holdtime  Type Protocol
ipi-2.lab.jan1.us.ipa.net xe48        3c2c.99c0.00aa      Up     26        L1L2 IS-IS
ipi-1.lab.jan1.us.ipa.net#show mpls ilm-table
Codes: > - installed ILM, * - selected ILM, p - stale ILM
        K - CLI ILM, T - MPLS-TP, s - Stitched ILM
       S - SNMP, L - LDP, R - RSVP, C - CRLDP
       B - BGP , K - CLI , V - LDP_VC, I - IGP_SHORTCUT
       O - OSPF/OSPF6 SR, i - ISIS SR, k - SR CLI
       P - SR Policy, U - unknown

Code    FEC/VRF/L2CKT    ILM-ID      In-Label    Out-Label   In-Intf    Out-Intf/VRF       Nexthop
   i>     4           16101       Nolabel     N/A        N/A    
   B>   evpn:1             3           17          Nolabel     N/A        N/A    
   B>   evpn:100           1           16          Nolabel     N/A        N/A    
   B>   evpn:1             2           640         Nolabel     N/A        N/A    
   P>     7           20          3           N/A        xe48   
   i>     5           26240       3           N/A        xe48   
   i>     6           16102       3           N/A        xe48   

Now we can see that we have a clns/isis neighbor with ipi-2 as well as learned labels. We can see both device’s node-sids in the label table on ipi-1.

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Next we can build EVPN on top of the underlay to begin delivering services. First we have to build an EVPN BGP session between the two routers.

ipi-1.lab.jan1.us.ipa.net#show run bgp
router bgp 65000
 neighbor remote-as 65000
 neighbor update-source lo
 address-family l2vpn evpn
 neighbor activate
ipi-1.lab.jan1.us.ipa.net#show bgp l2vpn evpn summary
BGP router identifier, local AS number 65000
BGP table version is 32
1 BGP AS-PATH entries
0 BGP community entries

Neighbor                 V   AS   MsgRcv    MsgSen TblVer   InQ   OutQ    Up/Down   State/PfxRcd     AD  MACIP
MCAST    ESI  PREFIX-ROUTE              4 65000 22856      22856      32      0      0  6d18h34m               2      1      0
     1      0      0


Next we can start build services on top. First we’ll build an EVPN-VPWS service.

evpn mpls enable
evpn mpls vtep-ip-global
mac vrf BLUE
 route-target both evpn-auto-rt
evpn mpls id 100 xconnect target-mpls-id 2
 host-reachability-protocol evpn-bgp BLUE
interface xe46.10 switchport
 encapsulation dot1q 10
  map vpn-id 100

EVPN MPLS has to be enabled. *IMPORTANT* This requires a reboot. Next the vtep id needs to be set. These are global settings for the environment.

For the creation of the service we’ll start by making a mac vrf to generate the information needed to create a EVPN type 2 route (mac-ip).

Since this is VPWS it is considered a cross connect xconnect and a target is defined. This is the remote PE vpn-id, in this case 2.

Finally it is assigned to a switchport. It has to be a switchport with a type of access-if-evpn. This maps back to the EVPN mac-vrf via the xconnect. Anything arriving on xe46.10 with a dot1q tag of 10 is placed into this tunnel.

ipi-1.lab.jan1.us.ipa.net#show evpn mpls xconnect
EVPN Xconnect Info
AC-AC: Local-Cross-connect
AC-NW: Cross-connect to Network
AC-UP: Access-port is up
AC-DN: Access-port is down
NW-UP: Network is up
NW-DN: Network is down
NW-SET: Network and AC both are up

Local                            Remote       Connection-Details

================================ ============ ==========================================================================
VPN-ID       EVI-Name      MTU   VPN-ID       Source       Destination                   PE-IP           MTU   Type   NW
================================ ============ ==========================================================================
100          ----          1500  2            xe46.10      --- Single Homed Port ---     1500  AC-NW  NW

Total number of entries are 1
ipi-1.lab.jan1.us.ipa.net#show evpn mpls xconnect tunnel
EVPN-MPLS Network tunnel Entries
Source           Destination      Status        Up/Down       Update        local-evpn-id remote-evpn-id
========================================================================================================      Installed     01:31:06      01:31:06      100           2

Total number of entries are 1

The tunnels are up, installed, and ready for forwarding. We can see the CE macs as mac-ip routes in evpn.

ipi-1.lab.jan1.us.ipa.net#show bgp l2vpn evpn vrf BLUE
BGP table version is 1, local router ID is
Status codes: s suppressed, d damped, h history, a add-path, * valid, > best, i - internal,
              l - labeled, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete

[EVPN route type]:[ESI]:[VNID]:[relevent route informantion]
1 - Ethernet Auto-discovery Route
2 - MAC/IP Route
3 - Inclusive Multicast Route
4 - Ethernet Segment Route
5 - Prefix Route

    Network          Next Hop            Metric    LocPrf	Weight     Path  Peer          Encap
* i  [1]:[0]:[2]:[16]          0        100       0    i     MPLS
*>   [1]:[0]:[100]:[16]
                       0        100       32768  i  ----------      MPLS

Total number of prefixes 2

The mac addresses are sent via an EVPN type-2 route between PEs.

ipi-1.lab.jan1.us.ipa.net#show evpn mpls mac-table
                                                     EVPN MPLS MAC Entries
VNID       Interface VlanId    In-VlanId Mac-Addr       VTEP-Ip/ESI                    Type            Status     MAC mo
ve AccessPortDesc

Total number of entries are : 0

Since this is VPWS there are no macs learned on the device.

[email protected]# run ping
PING ( 56 data bytes
64 bytes from icmp_seq=0 ttl=64 time=21.531 ms
64 bytes from icmp_seq=1 ttl=64 time=22.124 ms

Success! The CEs can reach each other over the EVPN-VPWS circuit.


Now we’ll build an EVPN-VPLS service. The BGP setup is the same so we’ll focus solely on the differences. The first one being the vpn-id creation.

mac vrf ORANGE
 route-target both evpn-auto-rt
evpn mpls id 1
 host-reachability-protocol evpn-bgp ORANGE

There is no end point defined as a xconnect. All that is necessary is to bind the mac vrf to the evpn vpn id.

interface xe46.100 switchport
 encapsulation dot1q 100
  map vpn-id 1

Again, a switchport defined as an access-if-evpn is necessary. This is then mapped to the vpn-id for the VPLS service. In this case anything coming in with a dot1q tag of 100 will be placed into vpn-id 1.

ipi-1.lab.jan1.us.ipa.net#show evpn mpls mac-table
                                                     EVPN MPLS MAC Entries
VNID       Interface VlanId    In-VlanId Mac-Addr       VTEP-Ip/ESI                    Type            Status     MAC mo
ve AccessPortDesc

1          xe46.100  ----      ----      84c1.c132.5031                    Dynamic Local   -------    0
1          ----      ----      ----      84c1.c132.5032                    Dynamic Remote  -------    0

Total number of entries are : 2

Since this is a VPLS service MACs are learned both locally and remotely. The remote MAC is the MAC of the remote CE. This was learned via EVPN and from the VTEP

ipi-1.lab.jan1.us.ipa.net#show bgp l2vpn evpn mac-ip vrf ORANGE
ESI                            Eth-Tag     Mac-Address    IP-Address                              VNID/LABEL     L3VNID
   Nexthop         GW-Type         Encap
0                              1           84c1:c132:5031 --                                      17             0     --              MPLS
0                              1           84c1:c132:5032 --                                      17             0     --              MPLS

The type-2 routes are populated in the BGP table.

[email protected]# run ping
PING ( 56 data bytes
64 bytes from icmp_seq=0 ttl=64 time=21.894 ms
64 bytes from icmp_seq=1 ttl=64 time=22.159 ms

Success! We have reachability across the service.


IP Infusion is continuing to build their evpn/mpls deployment as well as segment routing. It is exciting to see these feature sets continue to mature as traditional LDP/VPLS deployments move to EVPN/MPLS. If you need assistance on the transition from LDP to segment routing or VPLS to EVPN reach out to IP Architechs.

Situational Awareness for Network Migrations

At IP Architechs we perform a lot of network migrations and it is no secret network migrations/ maintenance windows can be one of the most nerve-racking things for engineers, managers, and business leaders for a variety of reasons.

For the engineers the uncertainty might be caused by fear of failure, not being able to predict the outcome due to complexity, rushed on preparation to meet a deadline, or a litany of other reasons.

For managers and business leaders it might be more along the lines of; what happens if this goes wrong, how will this effect my bottom line, are there going to be 1000s of trouble tickets come 8/9am when everyone hits the office, and so on.

The Preparation

We’re going to look at this at the perspective of the engineer throughout. The prep work is probably one of the most important pieces of success. This is where you do many things including but not limited to:

  • building and testing the configuration to be implemented
  • making a rollback plan — this might be something as simple as move a cable and shut an interface or a multistep/multi-device plan
  • know the situation surrounding the window

Lets explore understanding the situation surrounding the window a some more. I’ll use some real examples here to help.

We were getting ready to change the internet edge deployment at an enterprise. We did all the prep and rollback planning. However, we were given a few constraints on downtime by the business. Additionally, all of the product teams had to join the call for verification due to the impact of the, relatively small, routing change. The next opportunity was going to be a few months out due to change freezes and the coordination of resources necessary.

So what did we learn by engaging outside of the technical realm?

  • We had tight timeframes which placed an increased emphasis on planning
  • We needed to have plans for things that could go wrong and resolution paths based on downtime constraints
  • although a low impact routing change it was a high impact business change
  • We needed to have clearly defined decision points on what would be cause for a rollback

The Execution

All the prep is done and it’s time to execute the change. We put in the first couple lines of the script and everything is going well. We get to the point where we need to clean up the old configuration. Then every engineers nightmare happens – everything starts to go down.

Okay what do we do now, we know based on the situation we don’t have a lot of time to work through the problem. We need to stay calm and start working through our decision trees made during the planning process.

Some quick troubleshooting revealed when we removed the no longer used virtual routing and forwarding (VRF) instance it shutdown the ports that we now in the global table. We put the VRF back, still unused, everything began to work as expected again.

Next the debate began, should we get TAC on the line to assist. There were still a few items to knock out in the change window to avoid a complete rollback. A majority of people wanted to “chase the rabbit” of what caused the VRF deletion to bring down the interface. However, this would not be a good use of our time. If we got TAC on the line and began to go down that rabbit hole there is no telling where it would have gone or how long it would have taken. The facts were leaving the unused VRF, although annoying to have extra config, didn’t effect performance as far as we could tell and we needed to get through the rest of the migration.

After a short debate we all agreed based on the circumstances of the migration, coordination efforts, business drivers, and still needing to get some more work done we would continue down the migration path. We also took the necessary logs for an initial case with TAC and opened a ticket in the morning. Would we get the same level of info/t-shooting on that problem? No, but we were able to complete the migration and follow up on the weird behavior at a safer time.


Sometimes, based on different circumstance, the right decision would be to get TAC on the line and work through the issue. The owners might decide everything can be down until it’s working as planned or anywhere in between. Often, things like physical access or travel will allow for longer down time/troubleshooting.

It is important to know the situation around the migration, why it’s happening, who’s involved, and keep awareness of those during the migration to make informed decisions with the owner to make everyone successful.

If you need help planning your migrations reach out to us.

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