IOSv

Overview

IOSv is an implementation of Cisco IOS that runs as a full virtual machine. The IOSv images are built from the Cisco IOS M/T train and support up to 16 GigabitEthernet interfaces. IOSv provides full layer-3 control-plane and data-plane functionality. Layer-2 switching is not supported, but layer-2 encapsulations, such as EoMPLS and L2TPv3, are supported.

Limitations

IOSv is performance limited when forwarding traffic. Achieved throughputs are ~2.8 Mb/s when passing traffic through one IOSv router, and ~2.4 Mb/s when chained over two routers. Baseline throughput bypassing the router was ~720 Mb/s.

Forwarding performance has been tested with iperf running a basic test.

IOSv Features

Supported Features

The following features are included in the IOSv image:

  • 802.1Q
  • AAA
  • ACL
  • BGP
  • DHCP
  • DNS
  • EEM
  • EIGRP
  • EoMPLS
  • Flex Netflow + TNF
  • GRE
  • ICMP
  • IGMP
  • IP SLA
  • IPSec
  • IPv6
  • ISIS
  • L2TPv3
  • MPLS
  • MPLS L2VPN
  • MPLS L3VPN
  • MPLS TE
  • Multicast
  • NAT
  • NTP
  • OSPF
  • PfR
  • PIM
  • PPPoE
  • RADIUS
  • RIP
  • SNMP
  • SSH
  • SYSLOG
  • TACACS
  • TFTP
  • VRF-LITE

Features that May Work

The following features have not been tested and are not officially supported, but they may work in the IOSv image:

  • HSRP
  • VRRP
  • GLBP
  • EZVPN
  • QoS
  • LISP
  • ZBFW
  • Performance Monitor

Unsupported Features

The following features are not supported by IOSv and are known not to work:

  • OTV
  • BFD
  • VPLS
  • Voice
  • AVC

Features Tested with CML

Each CML release is tested with the bundled version of IOSv. The tests validate the following features:

Test Name Result
CDP Pass
ping Pass
OSPF single-area Pass
NAT - static Pass
HSRP Pass
DHCP Pass
Routed subinterface Pass

The lab used for the tests is IOSv Feature Tests, which is one of the sample labs included with CML on the Tools > Sample Labs page.

IOSv Feature Test Topology

CDP

  • peer device is detected on the interface and listed in the CDP table.
  • Neighbor types: IOSv, IOSvL2, CSR1000V

Ping test

  • Sending ICMP Echo packets to the neighbor IP
  • Direct reachability and reachability via routing

OSPF Single-Area

  • loopback interfaces configured
  • point-to-point networks configured on links between routers
  • all interfaces in area 0
  • OSPF establishes connectivity
  • Can ping loopback interfaces on different routers

NAT: Static

  • Alpine Linux VM connected to the router, configured static IP on VM and on router interface
  • static translation configured on a router
  • loopback interface with the translated network configured, and included in OSPF
  • ping of the untranslated VM IP from the router
  • ping of the translated VM IP from a different router

HSRP

  • two IOSv router, interconnected by a IOSvL2 switch
  • Alpine VM connected to the switch
  • HSRP configured on the two routers
  • Ping between: VM IP to HSRP IP
  • Verification: ping between: VM IP to SVI IP; SVI IP to HSRP IP; VM and SVI IP to interface IP

DHCP

  • DHCP pool configured on a router
  • Alpine Linux VM connected through the IOSvL2 switch

Routed subinterface

  • created routed subinterface on two IOSv routers
  • Interconnected them over the IOSvL2 switch; configured interfaces as trunks; configured VLANs on IOSvL2
  • Configured an IP on the SVI for that VLAN on IOSvL2