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CGNAT on VSM in
5.1.1
What is VSM?
Virtualized Services Module(VSM) is virtualized
platform in ASR9K to host multiple Service
applications.
This document will be focusing on
CGN/CGNv6(NAT44) as an example .
VSM Architecture
SFP+
SFP+ Quad
SFP+ PHY
SFP+
Intel
Cavecreek
chipset
XAUI
PCIe
48-Port
Niantic
switch
Crypto/DPI
Assist
32GB
DDR3
Ivy
Bridge
Niantic
Crypto/DPI
Assist
32GB
DDR3
Ivy
Bridge
32GB
DDR3
Ivy
Bridge
Fabric
ASIC 0
Typhoon
NPU
Fabric
ASIC 1
Niantic
Niantic
Niantic
48
ports
10GE
Niantic
Crypto/DPI
Assist
32GB
DDR3
Typhoon
NPU
Ivy
Bridge
B
A
C
K
P
L
A
N
E
Niantic
Niantic
Crypto/DPI
Assist
Application Processor Module (APM)
Service Infra Module (SIM)
VSM Hardware
•
•
•
•
Intel x86 Ivy Bridge CPU
1 Intel CPU with 10 cores
Total of 4 CPU with 40 Cores.
With Intel Hyper-threading technology total of 80 cores for
4CPU; 20 cores per CPU can be achieved.
• Intel Cavecreek Chipset provides Crypto/DPI assist
functionality.
Virtualized Software Infrastructure
KVM hypervisor runs on Linux.
Multiple Service Applications can be hosted.
Service chaining of applications can be achieved
in two ways:
1) Via static route
2) Via OnePK
Interface Terminologies
a) SVI Infra (identified by ‘interface ServiceInfra’) –used to send
SVI and CGv6 related control/mgmt traffic between XR and Linux
side
b) SVI App (identified by ‘interface ServiceApp’) –used to send
CGv6 data traffic to/from CGv6 applications.
Service Instantiation and
Configuration
Installing the CGv6 ova package
Step1 :
install 5.1.1 IOS-XR image along with services.pie and services-infra.pie.
Step 2:
copy the cgn.ova file to RSP (eg: disk0:)
Step 3 : Enable virtual-service
RP/0/RP0/CPU0:Starscream-UI-va(config)#virtual-service enable
RP/0/RP0/CPU0:Starscream-UI-va(config)#
Step 4: Install CGN VM , 0/3/CPU0 is location of VSM card.
RP/0/RP0/CPU0:Starscream-UI-va#virtual-service install name cgn123
package disk0:vsmcgv6_ivybridge.ova node 0/3/CPU0
CGv6 Installation status
Step 5: Status of Installation
RP/0/RP0/CPU0:Starscream-UI-va#sh virtual-service list
Virtual Service List:
Name
Status
Package Name
Node Name
______________________________________________________________________________
cgn123
Installing
vsmcgv6_ivybridge.ova 0/3/CPU0
RP/0/RP0/CPU0:Starscream-UI-va#sh virtual-service list
Virtual Service List:
Name
Status
Package Name
Node Name
______________________________________________________________________________
cgn123
Installed
vsmcgv6_ivybridge.ova 0/3/CPU0
RP/0/RP0/CPU0:Starscream-UI-va#
CGv6 VM activate
Step 6: Configure CGv6 VM
RP/0/RP0/CPU0:Starscream-UI-va(config)#virtual-service cgn123
RP/0/RP0/CPU0:Starscream-UI-va(config-virt-service)# vnic interface TenGigE0/3$
RP/0/RP0/CPU0:Starscream-UI-va(config-virt-service)# vnic interface TenGigE0/3$
RP/0/RP0/CPU0:Starscream-UI-va(config-virt-service)# vnic interface TenGigE0/3$
RP/0/RP0/CPU0:Starscream-UI-va(config-virt-service)# vnic interface TenGigE0/3$
RP/0/RP0/CPU0:Starscream-UI-va(config-virt-service)# vnic interface TenGigE0/3$
RP/0/RP0/CPU0:Starscream-UI-va(config-virt-service)# vnic interface TenGigE0/3$
RP/0/RP0/CPU0:Starscream-UI-va(config-virt-service)# vnic interface TenGigE0/3$
RP/0/RP0/CPU0:Starscream-UI-va(config-virt-service)# vnic interface TenGigE0/3$
RP/0/RP0/CPU0:Starscream-UI-va(config-virt-service)# vnic interface TenGigE0/3$
RP/0/RP0/CPU0:Starscream-UI-va(config-virt-service)# vnic interface TenGigE0/3$
RP/0/RP0/CPU0:Starscream-UI-va(config-virt-service)# vnic interface TenGigE0/3$
RP/0/RP0/CPU0:Starscream-UI-va(config-virt-service)# vnic interface TenGigE0/3$
RP/0/RP0/CPU0:Starscream-UI-va(config-virt-service)#commit
RP/0/RP0/CPU0:Starscream-UI-va(config-virt-service)#activate
RP/0/RP0/CPU0:Starscream-UI-va(config-virt-service)#commit
Step 7: Check the status of the CGv6 VM
RP/0/RP0/CPU0:Starscream-UI-va#sh virtual-service list
Virtual Service List:
Name
Status
Package Name
Node Name
______________________________________________________________________________
cgn123
Activated
vsmcgv6_ivybridge.ova 0/3/CPU0
RP/0/RP0/CPU0:Starscream-UI-va#
VSM-NAT44
Basic Configuration Steps
 Install asr9k-services-p.pie
Install asr9k-services-infra.pie
Int ServiceInfra1
IPv4:200.1.1.1/24
Ingress LC
VSM
Egress LC
VRF “Nat-inside”
VRF “Nat-outside”
CGN “cgn123/nat44”
Public IPv4 Pool (Natinside to Nat-outside):
100.2.0.0/24
Int Gige 0/6/1/13
VRF: Nat-inside
IPv4:31.1.1.1/24
int ServiceApp 1
VRF: Nat-inside
IPv4: 14.1.1.1/24
Service-Type: cgn123/nat44
router static
vrf Nat-inside
address-family ipv4 unicast
0.0.0.0/0 ServiceApp1
Int Gige 0/6/1/14
[VRF: Nat-outside]
IPv4:41.1.1.1/24
int ServiceApp 2
[VRF: Nat-outside]
IPv4: 15.1.1.1/24
Service-Type: cgn123/nat44
router static
[vrf Nat-outside]
address-family ipv4 unicast
100.2.0.0/24 ServiceApp2
Getting started for CGv6/CGNAT
•
Sample Ingress/Egress LC configuration:
vrf Nat-inside
address-family ipv4 unicast
interface GigabitEthernet0/6/1/13.100
vrf Nat-inside
ipv4 address 31.1.1.1 255.255.255.0
load-interval 30
encapsulation dot1q 100
vrf Nat-outside
address-family ipv4 unicast
interface GigabitEthernet0/6/1/14.100
vrf Nat-outside
ipv4 address 41.1.1.1 255.255.255.0
load-interval 30
encapsulation dot1q 100
Service CGN and service-type
******** CGN instance *******
service cgn cgn123
service-location preferred-active 0/3/CPU0
*****CGNAT service-type ******
service-type nat44 nat123
portlimit 65535
inside-vrf Nat-inside
map outside-vrf Nat-outside address-pool 100.2.0.0/24
!
protocol udp
session initial timeout 65535
session active timeout 65535
!
protocol tcp
session initial timeout 65535
session active timeout 65535
!
Service interfaces
interface ServiceInfra1
ipv4 address 75.1.1.1 255.255.255.0
service-location 0/3/CPU0
ServiceApp interfaces per vrf along with service cgn and service-type.
interface ServiceApp1
vrf Nat-inside
ipv4 address 14.1.1.1 255.255.255.0
service cgn cgn123 service-type nat44
interface ServiceApp2
vrf Nat-outside
ipv4 address 15.1.1.1 255.255.255.0
service cgn cgn123 service-type nat44
Static routes
Static route for Inside-to-outside; Redirect all traffic to Inside ServiceApp
interface:
vrf Nat-inside
address-family ipv4 unicast
0.0.0.0/0 ServiceApp1
Static route for Outside-to-inside traffic; IP address should match Public
pool configured under service cgn:
vrf Nat-outside
address-family ipv4 unicast
100.2.0.0/24 ServiceApp2
VSM-NAT44
sh cgn nat44 nat123 insidetranslation protocol udp inside-vrf
Nat-inside inside-address 31.1.1.2
port start 1 end 65535
Inside to outside translation
Int ServiceInfra1
IPv4:200.1.1.1/24
Ingress LC
VRF “Nat-inside”
VSM
Fib lookup happens
and traffic passes to
the outside-vrf on
the Egress LC
VRF “Nat-outside”
Egress LC
CGN “cgn123/nat44”
Src:31.1.1.2:1000
Dest: 41.1.1.2:1000
Public IPv4 Pool (Nat-inside to
Nat-outside): 100.2.0.0/24
Nat entry created:
31.1.1.2:1000 | 100.2.0.52:1000
int ServiceApp 1
VRF: Nat-inside
IPv4: 14.1.1.1/24
Service-Type: cgn123/nat44
Int Gige 0/6/1/14
[VRF: Nat-outside]
IPv4:41.1.1.1/24
Src:100.2.0.52:1000
Dest:41.1.1.2:1000
Inside-to-Outside Packet flow
1)
2)
3)
4)
Inside vrf is connected to a traffic Generator
Packet enters from private Inside VRF to the ingress Linecard.
Static route from inside vrf redirects all traffic to ServiceApp1 on VSM.
CGNAT application does the NAT processing for the packet and assigns a public IP address
from the public pool creating a NAT entry.
5) After the Nat translation forwarding lookup will be done for destination address in the
outside vrf and packet is sent to the Egress LC interface.
6) Egress line card send the packet to the Public side connected to another traffic generator.
VSM-NAT44
sh cgn nat44 nat123
outside-translation protocol
udp outside-vrf Nat-outside
outside-address 100.2.0.52
port start 1 end 65535
Outside to Inside translation
Ingress LC
VSM
Egress LC
VRF “Nat-inside”
VRF “Nat-outside”
CGN “cgn123/nat44”
Public IPv4 Pool (Natinside to Nat-outside):
100.2.0.0/24
Int Gige 0/6/1/13
VRF: Nat-inside
IPv4:31.1.1.1/24
Fib lookup happens
and traffic passes to
the inside-vrf on the
Egress LC
Int Gige 0/6/1/14
[VRF: Nat-outside]
IPv4:41.1.1.1/24
int ServiceApp 2
[VRF: Nat-outside]
IPv4: 15.1.1.1/24
Service-Type: cgn123/nat44
Src: 41.1.1.2:1000
Dest:100.2.0.52:1000
Outside to Inside Packet flow
(reverse-nat)
1) Packet enters from Outside vrf - Public side
2) Based on Static route defined packet should be forwarded to the VSM card via the
ServiceApp2 in the outside-vrf.
3) CGNAT application does the Nat processing and looks for corresponding NAT entry if present.
If not it drops the packet. If the entry is present then it replaces destination ip and port with
the corresponding Private IP address.
4) After the Reverse Nat translation forwarding lookup will be done for the destination IP
address in the inside vrf and packet is sent to the Egress LC interface
5) Egress line card send the packet out to the Private side/ inside vrf.
Caveats in 5.1.1
 VSM on Cluster is not supported
 Commit replace and rollback:
i) Commit replace does not have this restriction but its safer to
deactivate Virtual- services in all cases.
ii) Rollback:Virtual-services need to be deactivated before doing
config rollback.
 IP address configuration is not supported on the Tengig interfaces of the
VSM LC.
 4 Front Panel SFP+ ports are not enabled and cannot be used.
CGNAT Show commands
Inside-to-outside translation:
sh cgn nat44 nat123 inside-translation protocol udp inside-vrf Nat-inside-101 insideaddress 32.1.1.2 port start 1 end 65535
RP/0/RP1/CPU0:Starscream-UI-va#sh cgn nat44 nat123 inside-translation protocol$
Inside-translation details
--------------------------NAT44 instance : nat123
Inside-VRF : Nat-inside-101
-------------------------------------------------------------------------------------------Outside
Protocol Inside
Outside
Translation Inside Outside
Address
Source
Source
Type
to
to
Port
Port
Outside Inside
Packets Packets
-------------------------------------------------------------------------------------------101.2.0.58
udp 1000
34656
dynamic
1805831 1294025
RP/0/RP1/CPU0:Starscream-UI-va#
Outside-to-Inside Translation:
RP/0/RP0/CPU0:va#SH cgn nat44 nat123 outside-translation protocol udp
outside-address 101.2.0.58 port start 1 end 65535
Outside-translation details
--------------------------NAT44 instance : nat123
Outside-VRF : default
-------------------------------------------------------------------------------------------Inside
Protocol Outside Inside
Translation Inside Outside
Address
Destination Destination Type
to
to
Port
Port
Outside Inside
Packets Packets
-------------------------------------------------------------------------------------------32.1.1.2
udp 34656
1000
dynamic
107491158
101560603
RP/0/RP0/CPU0:va#
Cef commands
RP/0/RP0/CPU0:va#sh cef vrf Nat-inside 31.1.1.2 location 0/3/CPU0
31.1.1.0/24, version 19, attached, connected, internal 0xc0000c1 0x0 (ptr 0x7c12a064) [1], 0x0 (0x7c071008), 0x0 (0x0)
Updated Jan 22 15:17:43.521
remote adjacency to GigabitEthernet0/6/1/13.100
Prefix Len 24, traffic index 0, precedence n/a, priority 0
via GigabitEthernet0/6/1/13.100, 2 dependencies, weight 0, class 0 [flags 0x8]
path-idx 0 NHID 0x0 [0x7e1624d8 0x0]
remote adjacency
RP/0/RP0/CPU0:va#
RP/0/RP0/CPU0:va#sh cef vrf Nat-outside 101.2.0.58 location 0/3/CPU0
0.0.0.0/0, version 0, proxy default, default route handler, drop adjacency, internal 0x4002021 0x0 (ptr 0x7c1241e4) [1],
0x0 (0x7c066290), 0x0 (0x0)
Updated Jan 22 15:17:24.341
Prefix Len 0, traffic index 0, precedence n/a, priority 0
via point2point, 144 dependencies, weight 0, class 0 [flags 0x0]
path-idx 0 NHID 0x0 [0x7bacf23c 0x0]
next hop point2point
drop adjacency
RP/0/RP0/CPU0:va#
CGNAT Statistics summary
RP/0/RP0/CPU0:va#sh cgn nat44 nat123 statistics
Statistics summary of NAT44 instance: 'nat123'
Number of active translations: 14
Number of sessions: 100
Translations create rate: 0
Translations delete rate: 0
Inside to outside forward rate: 67875
Outside to inside forward rate: 8539
Inside to outside drops port limit exceeded: 0
Inside to outside drops system limit reached: 0
Inside to outside drops resource depletion: 0
No translation entry drops: 13
PPTP active tunnels: 0
PPTP active channels: 0
PPTP ctrl message drops: 0
Number of subscribers: 14
Drops due to session db limit exceeded: 0
Drops due to source ip not configured: 0
Pool address totally free: 498
Pool address used: 14
Pool address usage:
------------------------------------------------External Address
Ports Used
------------------------------------------------200.2.0.48
1
200.2.0.49
1
200.2.0.50
1
200.2.0.51
1
200.2.0.53
1
200.2.0.56
1