Contents

Introduction

Prerequisites

Requirements

Components Used

Background Information

Configure

Network Diagram

Configurations

Verify

Troubleshoot

Introduction

This document describes the IOS upgrade order for a specific deployment Model of the Overlay Transport Virtualization (OTV) on ASR1000 Family in a multihoming design setup.

Prerequisites

Requirements

Cisco recommends that you have knowledge of these topics:

- Basic Knowledge of the ASR 1000 Platform architecture

- Basic Knowledge of ASR1000 OTV Unicast Adjacency Server Configuration

- Basic knowledge of the Multihoming design

Components Used

The information in this document is based on the ASR 1001 with Cisco IOS®Versionasr1001-universalk9.03.10.03.S.153-3.S3-ext.bin.

The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, make sure that you understand the potential impact of any command.

Background Information

If possible, multihoming is always recommended because it adds another layer of redundancy and scalability. Note that the multihoming of Cisco ASR 1000 Series and other Cisco platforms within a single site is not supported.

Configure

Network Diagram

Configurations

Here is the configuration for both the routers on site A:

SITEA-ROUTER1#sh run

Building configuration...

otv site bridge-domain 1

otv isis hello-interval 3

!

otv fragmentation join-interface Port-channel19

otv site-identifier 0000.0000.0003

!

!

interface Port-channel19

description OTV Layer 3 to Distribution

mtu 9216

ip address 10.23.1.124 255.255.255.248

no ip redirects

load-interval 30

no negotiation auto

!

interface Overlay1

description Overlay Network

no ip address

otv join-interface Port-channel19

otv vpn-name DRT-CDC_Overlay

otv use-adjacency-server 172.31.1.212 unicast-only

otv adjacency-server unicast-only

otv isis hello-interval 3

service instance 6 ethernet

encapsulation dot1q 6

bridge-domain 6

!

service instance 1011 ethernet

encapsulation dot1q 1011

bridge-domain 1011

!

!

interface GigabitEthernet0/0/0

mtu 9216

no ip address

negotiation auto

cdp enable

service instance 1 ethernet

encapsulation dot1q 1

bridge-domain 1

!

service instance 6 ethernet

encapsulation dot1q 6

bridge-domain 6

!

service instance 1011 ethernet

encapsulation dot1q 1011

bridge-domain 1011

!

interface GigabitEthernet0/0/1

mtu 9216

no ip address

negotiation auto

cdp enable

channel-group 19 mode active

!

interface GigabitEthernet0/0/2

mtu 9216

no ip address

negotiation auto

cdp enable

channel-group 19 mode active

SITEA-ROUTER2#sh run

Building configuration...

otv site bridge-domain 1

otv isis hello-interval 3

!

otv fragmentation join-interface Port-channel20

otv site-identifier 0000.0000.0003

!

!

interface Loopback0

ip address 192.168.1.1 255.255.255.255

!

interface Port-channel20

description OTV Layer 3 to Distribution

mtu 9216

ip address 10.23.1.164 255.255.255.248

no ip redirects

load-interval 30

no negotiation auto

!

interface Overlay1

description Overlay Network

no ip address

otv join-interface Port-channel20

otv vpn-name DRT-CDC_Overlay

otv use-adjacency-server 172.31.1.212 10.23.1.124 unicast-only

otv isis hello-interval 3

service instance 6 ethernet

encapsulation dot1q 6

bridge-domain 6

!

service instance 1011 ethernet

encapsulation dot1q 1011

bridge-domain 1011

!

!

interface GigabitEthernet0/0/0

mtu 9216

no ip address

negotiation auto

cdp enable

service instance 1 ethernet

encapsulation dot1q 1

bridge-domain 1

!

service instance 6 ethernet

encapsulation dot1q 6

bridge-domain 6

!

service instance 1011 ethernet

encapsulation dot1q 1011

bridge-domain 1011

!

!

interface GigabitEthernet0/0/1

mtu 9216

no ip address

negotiation auto

cdp enable

channel-group 20 mode active

!

interface GigabitEthernet0/0/2

mtu 9216

no ip address

negotiation auto

cdp enable

channel-group 20 mode active

!

Here is the configuration for both the routers on site B:

SITEB-ROUTER1#SH RUN

Building configuration...

otv site bridge-domain 1

otv isis hello-interval 3

!

otv fragmentation join-interface Port-channel19

otv site-identifier 0000.0000.0002

!

interface Port-channel19

description OTV Layer 3 to Distribution

mtu 9216

ip address 172.31.1.212 255.255.255.248

no ip redirects

load-interval 30

no negotiation auto

!

interface Overlay1

description Overlay Network with CDC

no ip address

otv join-interface Port-channel19

otv vpn-name DRT-CDC_Overlay

otv adjacency-server unicast-only

otv isis hello-interval 3

service instance 6 ethernet

encapsulation dot1q 6

bridge-domain 6

!

service instance 1011 ethernet

encapsulation dot1q 1011

bridge-domain 1011

!

!

interface GigabitEthernet0/0/0

mtu 9216

no ip address

negotiation auto

cdp enable

service instance 1 ethernet

encapsulation untagged

bridge-domain 1

!

service instance 6 ethernet

encapsulation dot1q 6

bridge-domain 6

!

service instance 1011 ethernet

encapsulation dot1q 1011

bridge-domain 1011

!

!

interface GigabitEthernet0/0/1

mtu 9216

no ip address

negotiation auto

cdp enable

channel-group 19 mode active

!

interface GigabitEthernet0/0/2

mtu 9216

no ip address

negotiation auto

cdp enable

channel-group 19 mode active

SITEB-ROUTER2#SH RUN

Building configuration...

otv site bridge-domain 1

otv isis hello-interval 3

!

otv fragmentation join-interface GigabitEthernet0/0/0

otv fragmentation join-interface GigabitEthernet0/0/1

otv fragmentation join-interface GigabitEthernet0/0/2

otv fragmentation join-interface GigabitEthernet0/0/3

otv fragmentation join-interface Port-channel20

otv fragmentation join-interface Tunnel0

otv site-identifier 0000.0000.0002

!

interface Port-channel20

description OTV Layer 3 to Distribution

mtu 9216

ip address 172.31.1.220 255.255.255.248

no ip redirects

load-interval 30

no negotiation auto

!

interface Overlay1

description Overlay Network with CDC

no ip address

otv join-interface Port-channel20

otv vpn-name DRT-CDC_Overlay

otv use-adjacency-server 172.31.1.212 10.23.1.124 unicast-only

otv isis hello-interval 3

service instance 6 ethernet

encapsulation dot1q 6

bridge-domain 6

!

service instance 1011 ethernet

encapsulation dot1q 1011

bridge-domain 1011

!

!

interface GigabitEthernet0/0/0

mtu 9216

no ip address

negotiation auto

cdp enable

service instance 1 ethernet

encapsulation untagged

bridge-domain 1

!

service instance 6 ethernet

encapsulation dot1q 6

bridge-domain 6

!

service instance 1011 ethernet

encapsulation dot1q 1011

bridge-domain 1011

!

!

interface GigabitEthernet0/0/1

mtu 9216

no ip address

negotiation auto

cdp enable

channel-group 20 mode active

!

interface GigabitEthernet0/0/2

mtu 9216

no ip address

negotiation auto

cdp enable

channel-group 20 mode active

Verify

Use this section in order to confirm that your configuration works properly.

To verify if the set-up is working as configured you need the same basic commands you use for any OTV set up.

The list of outputs that are collected to verify the set up :

- Show otv

- Show otv adjacency

SITEA-ROUTER1#sh otv

Overlay Interface Overlay1

VPN name                 : DRT-CDC_Overlay

VPN ID                   : 1

State                    : UP

AED Capable              : Yes

Join interface(s)        : Port-channel19

Join IPv4 address        : 10.23.1.124

Tunnel interface(s)      : Tunnel0

Encapsulation format     : GRE/IPv4

Site Bridge-Domain       : 1

Capability               : Unicast-only

Is Adjacency Server      : Yes

Adj Server Configured    : Yes

Prim/Sec Adj Svr(s)      : 172.31.1.212

OTV instance(s)          : 0

FHRP Filtering Enabled   : Yes

ARP Suppression Enabled  : Yes

ARP Cache Timeout        : 600 seconds

SITEA-ROUTER2#sh otv de

Overlay Interface Overlay1

VPN name                 : DRT-CDC_Overlay

VPN ID                   : 1

State                    : UP

AED Capable              : Yes

Join interface(s)        : Port-channel20

Join IPv4 address        : 10.23.1.164

Tunnel interface(s)      : Tunnel0

Encapsulation format     : GRE/IPv4

Site Bridge-Domain       : 1

Capability               : Unicast-only

Is Adjacency Server      : No

Adj Server Configured    : Yes

Prim/Sec Adj Svr(s)      : 172.31.1.212/10.23.1.124

OTV instance(s)          : 0

FHRP Filtering Enabled   : Yes

ARP Suppression Enabled  : Yes

ARP Cache Timeout        : 600 seconds

SITEB-ROUTER1#sh otv de

Overlay Interface Overlay1

VPN name                 : DRT-CDC_Overlay

VPN ID                   : 1

State                    : UP

AED Capable              : Yes

Join interface(s)        : Port-channel19

Join IPv4 address        : 172.31.1.212

Tunnel interface(s)      : Tunnel0

Encapsulation format     : GRE/IPv4

Site Bridge-Domain       : 1

Capability               : Unicast-only

Is Adjacency Server      : Yes

Adj Server Configured    : No

Prim/Sec Adj Svr(s)      : None

OTV instance(s)          : 0

FHRP Filtering Enabled   : Yes

ARP Suppression Enabled  : Yes

SITEB-ROUTER2#sh otv de

Overlay Interface Overlay1

VPN name                 : DRT-CDC_Overlay

VPN ID                   : 1

State                    : UP

AED Capable              : Yes

Join interface(s)        : Port-channel20

Join IPv4 address        : 172.31.1.220

Tunnel interface(s)      : Tunnel0

Encapsulation format     : GRE/IPv4

Site Bridge-Domain       : 1

Capability               : Unicast-only

Is Adjacency Server      : No

Adj Server Configured    : Yes

Prim/Sec Adj Svr(s)      : 172.31.1.212/10.23.1.124

OTV instance(s)          : 0

FHRP Filtering Enabled   : Yes

ARP Suppression Enabled  : Yes

ARP Cache Timeout        : 600 seconds

Troubleshoot

This section provides information you can use in order to troubleshoot your configuration.

SITEA-ROUTER1 is the primary Authoritative Edge Device (AED) for SITE A and SITEB-ROUTER1 is the primary AED for SITE B.

You upgrade the active AED on site B and backup AED on site A fromasr1001-universalk9.03.10.03.S.153-3.S3-ext.bin to asr1001-universalk9.03.16.03.S.155-3.S3-ext.bin.

The devices were upgraded successfully but these were the issues that were seen after the upgrade:

- OTV Adjacency went down

- AED Capable state changed to NO and overlay neighbor version mismatch message was seen

- Configured VLANS went into inactive(NFC) Not Forward Capable state.

- inter-DC & intra-DC communication stopped completely

Primary/active AED on SITEB

SITEB-ROUTER1#sh otv de

Overlay Interface Overlay1

VPN name                 : DRT-CDC_Overlay

VPN ID                   : 1

State                    : UP

Fwd-capable              : No

Fwd-ready                : No

AED-Server               : No

AED Capable              : No, overlay neighbor version mismatch

Join interface(s)        : Port-channel19

Join IPv4 address        : 172.31.1.212

Tunnel interface(s)      : Tunnel0

Encapsulation format     : GRE/IPv4

Site Bridge-Domain       : 1

Capability               : Unicast-only

Is Adjacency Server      : Yes

Adj Server Configured    : No

Prim/Sec Adj Svr(s)      : None

OTV instance(s)          : 0

FHRP Filtering Enabled   : Yes

ARP Suppression Enabled  : Yes

ARP Cache Timeout        : 600 seconds

SITEB-ROUTER1##sh otv vl

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    6    6    -                    inactive(NFC)       Gi0/0/0:SI6

0    186  186  -                    inactive(NFC)       Gi0/0/0:SI186

0    1011 1011 -                    inactive(NFC)       Gi0/0/0:SI1011

0    1030 1030 -                    inactive(NFC)       Gi0/0/0:SI1030

Total VLAN(s): 4

Secondary/backup AED on SITEA

SITEA-ROUTER2#sh otv

Overlay Interface Overlay1

VPN name                 : DRT-CDC_Overlay

VPN ID                   : 1

State                    : UP

Fwd-capable              : No

Fwd-ready                : No

AED-Server               : No

AED Capable              : No, overlay neighbor version mismatch

Join interface(s)        : Port-channel20

Join IPv4 address        : 10.23.1.164

Tunnel interface(s)      : Tunnel0

Encapsulation format     : GRE/IPv4

Site Bridge-Domain       : 1

Capability               : Unicast-only

Is Adjacency Server      : No

Adj Server Configured    : Yes

Prim/Sec Adj Svr(s)      : 172.31.1.212/10.23.1.124

OTV instance(s)          : 0

FHRP Filtering Enabled   : Yes

ARP Suppression Enabled  : Yes

ARP Cache Timeout        : 600 seconds

SITEA-ROUTER2#sh 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    6    6    -                    inactive(NFC)       Gi0/0/0:SI6

0    186  186  -                    inactive(NFC)       Gi0/0/0:SI186

0    1011 1011 -                    inactive(NFC)       Gi0/0/0:SI1011

Total VLAN(s): 3

This issue basically occurs since ISIS which runs at the backend has seen many changes to facilitate OTV Fast Convergence (FC). Hence, images which are pre FC and post FC will not work together.

In releases pre FC: the AED election runs in parallel, independently on each Edge Device (ED) in the site. Since the AED election is triggered independently and is uncoordinated among the multiple edge devices in the site, a short wait period of blackholing is required to ensure that two or more edge devices are not simultaneously AED and hence forwarding traffic for the same VLAN. This introduces a convergence delay when there are failures at an ED that is AED for some VLANs.

In addition, OTV traffic convergence upon an AED failure is dependent on the new AED at the site learning the local routing information and advertising the same to the remote sites. This dependency introduces delays that are non-deterministic and is also impacted by the scale of the routing databases. It is required to minimize the loss of existing traffic flows when there is a failure event on the edge devices to provide faster convergence of OTV deployed networks in such scenarios.

It is highly recommended that both ED’s which participate in OTV DC be on the same image. If we wish to upgrade to a different train it is recommended to bring the overlay interfaces down and upgrade all the four devices simultaneously and then after the upgrade bring the overlay interface up and adjacency will be established.