Contents

Introduction

Prerequisites

Requirements

Components Used

Background Information

Limitations

Configure

Challenges During Troubleshoot

Network Diagram

Configurations

Verify

Troubleshoot

Introduction

This document describes how to configure Border Gateway Protocol (BGP) IPv6 Flowspec on ASR1K.

Prerequisites

Requirements

Cisco recommends that you have knowledge of this topic:

- Platform Independent

Components Used

The information in this document is based on these software and hardware versions:

- IOS-XE

- ASR1000

- ASR9K

- ASR1K

- BGP

- Flowspec

- IPv6

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, ensure that you understand the potential impact of any command.

Background Information

Flowspec specifies procedures for the distribution of flow specification rules via BGP and defines the procedure to encode flow specification rules as Border Gateway Protocol Network Layer Reachability Information (BGP NLRI) which can be used in any application. It also defines application for the purpose of packet filtering in order to mitigate (distributed) denial of service attacks.

Limitations

These are the limitations for the configuration:

- A mix of address families is not allowed in flowspec rules.

- In multiple match scenario, only the first matching flowspec rule is applied.

- A maximum of 3000 flowspec rules is supported per system.

Configure

In this example, we have configured ASR9K as a controller and ASR1K as a PE, RR and Flowspec client.

This is the minimum configuration required for IPv6 Flowspec to work.

On controller to push the policy to PE/client:

class-map type traffic match-all FLOWSPEC

match destination-address ipv6 2001:db8::/32   <<<<< Match destination address/subnet.

end-class-map

!

policy-map type pbr FS_P

class type traffic FLOWSPEC                    <<<<< Apply class-map under policy-map.

drop

!

flowspec

address-family ipv4

service-policy type pbr FSP_V4

!

address-family ipv6

service-policy type pbr FS_P                  <<<<< Apply policy-map inside Flowspec under AF.

!

On PE/client is to enable IPv6 flowspec AF under BGP.

address-family ipv6 flowspec                   <<<<< Under ipv6 flowspec AF, activate the neighbor.

neighbor 10.192.202.5 activate

neighbor 10.192.202.5 validation off

To apply the flowspec policy on interface, "local-install interface-all" command is must under flowspec.

flowspec

local-install interface-all                    <<<<< Push the policy on interface.

- Based on the controller configuration, any traffic destined to 2001:db8::/32 should get dropped according to the policy.

- Keep the validation off for the neighbor under ipv6 address-family so that ASR1K doesn't check for the next-hop.

- Ideally, if the policy is in action, the counter is seen in the controller but in case if you want to see it on any other device, install flowspec policy on all user interfaces for which local-install interface-all command is required under flowspec.

Challenges During Troubleshoot

- If the underlay network is IPv4 and BGP flowspec runs for IPv6 then there is an issue of validation check on every-hop and causes an issue for IPv6 Flowspec policy. Hence, keep the validation off so that neighbor doesn't do validation check.

- Other than a controller, you cannot see the flowspec policy match/action counter. In order to check the counters, local-install interface-all is must under Flowspec (under AF). This command pushes the flow specification policy configuration on all interfaces of a device for the IPv4 and IPv6 address families, and on interfaces within a VRF instance.

Network Diagram

+----------------+              +-----------------+            +------------------+             +-----------------+

|                |              |                 |            |                  |             |                 |

|   Controller   +--------------+     PE/RR1      +------------+      PE/RR2      +-------------+      End-PE     |

|     ASR9K      |              |     CRR01       |            |      CRR02       |             |      DCPR01     |

+----------------+              +-----------------+            +------------------+             +-----------------+

Configurations

This configuration is based on the network diagram, the same as your setup.

Controller:

RP/0/RSP0/CPU0:Controller# show running-config

Mon Apr  8 16:33:36.578 UTC

Building configuration...

!! IOS XR Configuration 5.3.4

!! Last configuration change at Wed Apr  3 17:34:59 2019 by admin

!

hostname Controller

cdp

cdp advertise v1

!

class-map type traffic match-all FLOWSPEC

match destination-address ipv6 2001:db8::/32

end-class-map

!

class-map type traffic match-all V4_FLOWSPEC

match source-address ipv4 102.102.102.102 255.255.255.255

end-class-map

!

policy-map type pbr FS_P

class type traffic FLOWSPEC

drop

!

class type traffic class-default

!

end-policy-map

!

policy-map type pbr FSP_V4

class type traffic V4_FLOWSPEC

set dscp ef

!

class type traffic class-default

!

end-policy-map

!

interface Loopback0

ipv4 address 10.192.202.5 255.255.255.255

!

interface Loopback100

ipv4 address 102.102.102.102 255.255.255.255

ipv6 address 2001:db8::1/32

!

interface TenGigE0/0/0/0

ipv4 address 10.10.12.1 255.255.255.0

ipv6 address 2001:10:10:12::1/64

!

route-policy ALL

pass

end-policy

!

router static

address-family ipv4 unicast

203.202.143.33/32 TenGigE0/0/0/0

!

address-family ipv6 unicast

2003::/64 2001:10:10:12::2

!

!

router ospfv3 1

area 0

interface TenGigE0/0/0/0

network point-to-point

!

!

!

router bgp 64696

bgp router-id 10.192.202.5

address-family ipv4 unicast

network 102.102.102.102/32

!

address-family vpnv4 unicast

!

address-family ipv4 flowspec

!

address-family ipv6 flowspec

!

neighbor 203.202.143.33

remote-as 7474

ebgp-multihop 10

update-source Loopback0

address-family ipv4 unicast

route-policy ALL in

route-policy ALL out

!

address-family vpnv4 unicast

!

address-family ipv4 flowspec

route-policy ALL in

route-policy ALL out

!

address-family ipv6 flowspec

route-policy ALL in

route-policy ALL out

!

!

!

flowspec

local-install interface-all

address-family ipv4

service-policy type pbr FSP_V4

!

address-family ipv6

service-policy type pbr FS_P

!

!

end

PE/RR1:

CRR01#show running-config

Building configuration...

!

ipv6 unicast-routing

mpls label protocol ldp

!

spanning-tree extend system-id

flowspec

local-install interface-all

diagnostic bootup level minimal

!

interface Loopback0

ip address 203.202.143.33 255.255.255.255

ip ospf 1 area 0

!

interface Loopback1010

no ip address

ipv6 address 2001:DB8::10/32

!

interface TenGigabitEthernet0/0/0

ip address 10.10.12.2 255.255.255.0

ip ospf network point-to-point

cdp enable

ipv6 address 2001:10:10:12::2/64

!

interface TenGigabitEthernet0/0/3

ip address 10.10.23.2 255.255.255.0

ip ospf network point-to-point

ip ospf 1 area 0

cdp enable

ipv6 address 2003::1/64

mpls ip

!

router ospf 1

mpls ldp autoconfig

!

router bgp 7474

bgp router-id 203.202.143.33

bgp log-neighbor-changes

neighbor 10.192.202.5 remote-as 64696

neighbor 10.192.202.5 ebgp-multihop 10

neighbor 10.192.202.5 update-source Loopback0

neighbor 2001:10:10:12::1 remote-as 64696

neighbor 203.202.143.44 remote-as 7474

neighbor 203.202.143.44 update-source Loopback0

!

address-family ipv4

neighbor 10.192.202.5 activate

no neighbor 2001:10:10:12::1 activate

neighbor 203.202.143.44 activate

neighbor 203.202.143.44 route-reflector-client

exit-address-family

!

address-family ipv4 flowspec

neighbor 10.192.202.5 activate

neighbor 203.202.143.44 activate

neighbor 203.202.143.44 send-community both

neighbor 203.202.143.44 route-reflector-client

exit-address-family

!

address-family ipv6

neighbor 10.192.202.5 activate

neighbor 203.202.143.44 activate

neighbor 203.202.143.44 route-reflector-client

neighbor 203.202.143.44 send-label

exit-address-family

!

address-family ipv6 flowspec

neighbor 10.192.202.5 activate

neighbor 10.192.202.5 validation off

neighbor 203.202.143.44 activate

neighbor 203.202.143.44 send-community both

neighbor 203.202.143.44 route-reflector-client

neighbor 203.202.143.44 next-hop-self

exit-address-family

!

ip route 10.192.202.5 255.255.255.255 10.10.12.1

!

!

ipv6 route 2001:DB8::1/128 2001:10:10:12::1

!

end

PE/RR2:

CRR02#show running-config

Building configuration...

Current configuration : 7227 bytes

!

! Last configuration change at 18:21:29 UTC Mon Apr 8 2019

!

hostname CRR02

!

boot-start-marker

boot system flash bootflash:asr1000rpx86-universalk9.16.10.01a.SPA.bin

boot-end-marker

!

ipv6 unicast-routing

multilink bundle-name authenticated

!

spanning-tree extend system-id

flowspec

diagnostic bootup level minimal

!

interface Loopback0

ip address 203.202.143.44 255.255.255.255

ip ospf 1 area 0

!

interface TenGigabitEthernet1/0/0

ip address 10.10.23.3 255.255.255.0

ip ospf network point-to-point

ip ospf 1 area 0

cdp enable

ipv6 address 2003::2/64

mpls ip

!

interface TenGigabitEthernet1/0/1

ip address 10.10.34.3 255.255.255.0

ip ospf network point-to-point

ip ospf 1 area 0

cdp enable

!

router ospf 1

mpls ldp autoconfig

!

router bgp 7474

bgp router-id 203.202.143.44

bgp log-neighbor-changes

neighbor 203.202.143.33 remote-as 7474

neighbor 203.202.143.33 update-source Loopback0

neighbor 203.202.143.45 remote-as 7474

neighbor 203.202.143.45 update-source Loopback0

!

address-family ipv4

neighbor 203.202.143.33 activate

neighbor 203.202.143.45 activate

exit-address-family

!

address-family ipv4 flowspec

neighbor 203.202.143.33 activate

neighbor 203.202.143.45 activate

neighbor 203.202.143.45 send-community both

neighbor 203.202.143.45 route-reflector-client

exit-address-family

!

address-family ipv6

neighbor 203.202.143.33 activate

neighbor 203.202.143.33 send-label

exit-address-family

!

address-family ipv6 flowspec

neighbor 203.202.143.33 activate

neighbor 203.202.143.33 validation off

neighbor 203.202.143.45 activate

neighbor 203.202.143.45 send-community both

neighbor 203.202.143.45 route-reflector-client

exit-address-family

!

ipv6 route 2001:10:10:12::/64 2003::1

ipv6 route 2001:DB8::1/128 2003::1

!

end

End-PE:

DCPR01#show running-config

Building configuration...

!

hostname DCPR01

!

subscriber templating

!

ipv6 unicast-routing

!

flowspec

diagnostic bootup level minimal

!

interface Loopback0

ip address 203.202.143.45 255.255.255.255

ip ospf 1 area 0

!

interface TenGigabitEthernet1/3/0

ip address 10.10.34.4 255.255.255.0

ip ospf network point-to-point

ip ospf 1 area 0

cdp enable

ipv6 address 2001::1/64

!

router ospf 1

mpls ldp autoconfig

!

router bgp 7474

bgp router-id 203.202.143.45

bgp log-neighbor-changes

neighbor 203.202.143.44 remote-as 7474

neighbor 203.202.143.44 update-source Loopback0

!

address-family ipv4 flowspec

neighbor 203.202.143.44 activate

exit-address-family

!

address-family ipv6 flowspec

neighbor 203.202.143.44 activate

neighbor 203.202.143.44 validation off

exit-address-family

!

ipv6 route ::/0 TenGigabitEthernet1/3/0

!

end

Verify

PE/RR2:

CRR02#ping 2001:db8::1

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 2001:DB8::1, timeout is 2 seconds:

.....

Success rate is 0 percent (0/5)

CRR02#

Controller:

RP/0/RSP0/CPU0:Controller#show bgp ipv6 flowspec

Mon Apr  8 17:55:17.041 UTC

BGP router identifier 10.192.202.5, local AS number 64696

BGP generic scan interval 60 secs

Non-stop routing is enabled

BGP table state: Active

Table ID: 0x0   RD version: 20

BGP main routing table version 20

BGP NSR Initial initsync version 0 (Reached)

BGP NSR/ISSU Sync-Group versions 0/0

BGP scan interval 60 secs

Status codes: s suppressed, d damped, h history, * valid, > best

i - internal, r RIB-failure, S stale, N Nexthop-discard

Origin codes: i - IGP, e - EGP, ? - incomplete

Network            Next Hop            Metric LocPrf Weight Path

*> Dest:2001:db8::/0-32/56

::                                     0 i

Processed 1 prefixes, 1 paths

RP/0/RSP0/CPU0:Controller#show flowspec ipv6 detail

Mon Apr  8 17:55:36.786 UTC

AFI: IPv6

Flow           :Dest:2001:db8::/0-32

Actions      :Traffic-rate: 0 bps  (policy.1.FS_P.FLOWSPEC)

Statistics                        (packets/bytes)

Matched             :                  14/1652

Dropped             :                  14/1652

RP/0/RSP0/CPU0:BGL14.1.J.05-ASR-9000-1#

PE/RR1:

CRR01#show bgp ipv6 flowspec

BGP table version is 2, local router ID is 203.202.143.33

Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,

r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,

x best-external, a additional-path, c RIB-compressed,

t secondary path,

Origin codes: i - IGP, e - EGP, ? - incomplete

RPKI validation codes: V valid, I invalid, N Not found

Network          Next Hop            Metric LocPrf Weight Path

*>   Dest:2001:DB8::/0-32

::                                     0 64696 i

CRR01#

CRR01#show flowspec ipv6 detail

AFI: IPv6

Flow           :Dest:2001:DB8::/0-32

Actions      :Traffic-rate: 0 bps  (bgp.1)

Statistics                        (packets/bytes)

Matched             :                   4/456

Dropped             :                   4/456

CRR01#

Troubleshoot

There is currently no specific troubleshooting information available for this configuration.

Tip: If you open a case with 3.16.5S and hit with CSCva55510 bug id. Though it's not documented in the bug yet it applies for IPv6. This is confirmed from ASR1K BGP BU and is validated. Another bug CSCvp18767 is also filed for show command which is fixed in 16.12.1 hence better to use this release. However, IPv6 flowspec can work in any 16.x release.