.. _segment-routing:

###############
Segment Routing
###############

Segment Routing (SR) is a network architecture that is similar to 
source-routing.In this architecture, the ingress router adds a list of segments,
known as SIDs, to the packet as it enters the network. These segments represent
different portions of the network path that the packet will take.

The SR segments are portions of the network path taken by the packet, and are 
called SIDs. At each node, the first SID of the list is read, executed as a 
forwarding function, and may be popped to let the next node read the next SID of 
the list. The SID list completely determines the path where the packet is 
forwarded.

Segment Routing can be applied to an existing MPLS-based data plane and defines
a control plane network architecture. In MPLS networks, segments are encoded as
MPLS labels and are added at the ingress router. These MPLS labels are then 
exchanged and populated by Interior Gateway Protocols (IGPs) like IS-IS or OSPF 
which are running on most ISPs.


.. note:: Segment routing defines a control plane network architecture and
  can be applied to an existing MPLS based dataplane. In the MPLS networks,
  segments are encoded as MPLS labels and are imposed at the ingress router.
  MPLS labels are exchanged and populated by IGPs like IS-IS.Segment Routing
  as per RFC8667 for MPLS dataplane. It supports IPv4, IPv6 and ECMP and has
  been tested against Cisco & Juniper routers.however,this deployment is still
  EXPERIMENTAL for FRR .
 

IS-IS SR Configuration
----------------------

Segment routing (SR) is used by the IGP protocols to interconnect network
devices, below configuration shows how to enable SR on IS-IS:


.. note:: ``Known limitations:`` 

  No support for level redistribution (L1 to L2 or L2 to L1)

  No support for binding SID

  No support for SRLB

  Only one SRGB and default SPF Algorithm is supported



.. cfgcmd:: set protocols isis segment-routing global-block <high-label-value 
  | low-label-value> <label-value>

  Set the Segment Routing Global Block i.e. the label range used by MPLS to 
  store label in the MPLS FIB for Prefix SID. Note that the block size may 
  not exceed 65535.

.. cfgcmd:: set protocols isis segment-routing local-block <high-label-value 
  | low-label-value> <label-value>

  Set the Segment Routing Local Block i.e. the label range used by MPLS to 
  store label in the MPLS FIB for Prefix SID. Note that the block size may 
  not exceed 65535.Segment Routing Local Block, The negative command always 
  unsets both.

.. cfgcmd:: set protocols isis segment-routing maximum-label-depth <1-16>

  Set the Maximum Stack Depth supported by the router. The value depend of
  the MPLS dataplane.

.. cfgcmd:: set protocols isis segment-routing prefix <address> index value 
  <0-65535>
   
  A segment ID that contains an IP address prefix calculated by an IGP in the
  service provider core network. Prefix SIDs are globally unique, this value
  indentify it 

.. cfgcmd:: set protocols isis segment-routing prefix <address> index
   <no-php-flag | explicit-null| n-flag-clear>

   prefix. The ‘no-php-flag’ means NO Penultimate Hop Popping that allows SR 
   node to request to its neighbor to not pop the label. The ‘explicit-null’ 
   flag allows SR node to request to its neighbor to send IP packet with the 
   EXPLICIT-NULL label. The ‘n-flag-clear’ option can be used to explicitly
   clear the Node flag that is set by default for Prefix-SIDs associated to 
   loopback addresses. This option is necessary to configure Anycast-SIDs.


.. opcmd:: show isis segment-routing node

   Show detailed information about all learned Segment Routing Nodes

.. note:: more information related IGP  - :ref:`routing-isis`

   

OSPF SR  Configuration
----------------------

Segment routing (SR) is used by the IGP protocols to interconnect network
devices, below configuration shows how to enable SR on OSPF:

.. cfgcmd:: set protocols ospf parameters opaque-lsa

  Enable the Opaque-LSA capability (rfc2370),necessary to transport label 
  on IGP


.. cfgcmd:: set protocols ospf segment-routing global-block <high-label-value 
  | low-label-value> <label-value>

  Set the Segment Routing Global Block i.e. the label range used by MPLS to 
  store label in the MPLS FIB for Prefix SID. Note that the block size may 
  not exceed 65535.

.. cfgcmd:: set protocols ospf segment-routing local-block <high-label-value 
  | low-label-value> <label-value>

  Set the Segment Routing Local Block i.e. the label range used by MPLS to 
  store label in the MPLS FIB for Prefix SID. Note that the block size may 
  not exceed 65535.Segment Routing Local Block, The negative command always 
  unsets both.

.. cfgcmd:: set protocols ospf segment-routing maximum-label-depth <1-16>

  Set the Maximum Stack Depth supported by the router. The value depend of
  the MPLS dataplane.

.. cfgcmd:: set protocols ospf segment-routing prefix <address> index value 
  <0-65535>
   
  A segment ID that contains an IP address prefix calculated by an IGP in the
  service provider core network. Prefix SIDs are globally unique, this value
  indentify it 

.. cfgcmd:: set protocols ospf segment-routing prefix <address> index
   <no-php-flag | explicit-null| n-flag-clear>

   prefix. The ‘no-php-flag’ means NO Penultimate Hop Popping that allows SR 
   node to request to its neighbor to not pop the label. The ‘explicit-null’ 
   flag allows SR node to request to its neighbor to send IP packet with the 
   EXPLICIT-NULL label. The ‘n-flag-clear’ option can be used to explicitly
   clear the Node flag that is set by default for Prefix-SIDs associated to 
   loopback addresses. This option is necessary to configure Anycast-SIDs.

.. note:: more information related IGP  - :ref:`routing-ospf`

Configuration Example
---------------------

we described the configuration SR ISIS / SR OSPF using 2 connected with them to
share label information.

Enable IS-IS with Segment Routing (Experimental)
================================================

**Node 1:**

.. code-block:: none

  set interfaces loopback lo address '192.168.255.255/32'
  set interfaces ethernet eth1 address '192.0.2.1/24'

  set protocols isis interface eth1
  set protocols isis interface lo
  set protocols isis net '49.0001.1921.6825.5255.00'
  set protocols isis segment-routing global-block high-label-value '599'
  set protocols isis segment-routing global-block low-label-value '550'
  set protocols isis segment-routing prefix 192.168.255.255/32 index value '1'
  set protocols isis segment-routing prefix 192.168.255.255/32 index explicit-null
  set protocols mpls interface 'eth1'
  
**Node 2:**

.. code-block:: none

  set interfaces loopback lo address '192.168.255.254/32'
  set interfaces ethernet eth1 address '192.0.2.2/24'

  set protocols isis interface eth1
  set protocols isis interface lo
  set protocols isis net '49.0001.1921.6825.5254.00'
  set protocols isis segment-routing global-block high-label-value '599'
  set protocols isis segment-routing global-block low-label-value '550'
  set protocols isis segment-routing prefix 192.168.255.254/32 index value '2'
  set protocols isis segment-routing prefix 192.168.255.254/32 index explicit-null
  set protocols mpls interface 'eth1'
  
  
  
This gives us MPLS segment routing enabled and labels for far end loopbacks:

.. code-block:: none

  Node-1@vyos:~$ show mpls table
   Inbound Label  Type        Nexthop                Outbound Label
   ----------------------------------------------------------------------
   552            SR (IS-IS)  192.0.2.2              IPv4 Explicit Null <-- Node-2 loopback learned on Node-1
   15000          SR (IS-IS)  192.0.2.2              implicit-null
   15001          SR (IS-IS)  fe80::e87:6cff:fe09:1  implicit-null
   15002          SR (IS-IS)  192.0.2.2              implicit-null
   15003          SR (IS-IS)  fe80::e87:6cff:fe09:1  implicit-null

  Node-2@vyos:~$ show mpls table
   Inbound Label  Type        Nexthop               Outbound Label
   ---------------------------------------------------------------------
   551            SR (IS-IS)  192.0.2.1             IPv4 Explicit Null <-- Node-1 loopback learned on Node-2
   15000          SR (IS-IS)  192.0.2.1             implicit-null
   15001          SR (IS-IS)  fe80::e33:2ff:fe80:1  implicit-null
   15002          SR (IS-IS)  192.0.2.1             implicit-null
   15003          SR (IS-IS)  fe80::e33:2ff:fe80:1  implicit-null

Here is the routing tables showing the MPLS segment routing label operations:

.. code-block:: none

  Node-1@vyos:~$ show ip route isis
  Codes: K - kernel route, C - connected, S - static, R - RIP,
         O - OSPF, I - IS-IS, B - BGP, E - EIGRP, N - NHRP,
         T - Table, v - VNC, V - VNC-Direct, A - Babel, F - PBR,
         f - OpenFabric,
         > - selected route, * - FIB route, q - queued, r - rejected, b - backup
         t - trapped, o - offload failure

  I   192.0.2.0/24 [115/20] via 192.0.2.2, eth1 inactive, weight 1, 00:07:48
  I>* 192.168.255.254/32 [115/20] via 192.0.2.2, eth1, label IPv4 Explicit Null, weight 1, 00:03:39

  Node-2@vyos:~$ show ip route isis
  Codes: K - kernel route, C - connected, S - static, R - RIP,
         O - OSPF, I - IS-IS, B - BGP, E - EIGRP, N - NHRP,
         T - Table, v - VNC, V - VNC-Direct, A - Babel, F - PBR,
         f - OpenFabric,
         > - selected route, * - FIB route, q - queued, r - rejected, b - backup
         t - trapped, o - offload failure

  I   192.0.2.0/24 [115/20] via 192.0.2.1, eth1 inactive, weight 1, 00:07:46
  I>* 192.168.255.255/32 [115/20] via 192.0.2.1, eth1, label IPv4 Explicit Null, weight 1, 00:03:43


Enable OSPF with Segment Routing (Experimental):
================================================

**Node 1**

.. code-block:: none

  set interfaces loopback lo address 10.1.1.1/32
  set interfaces ethernet eth0 address 192.168.0.1/24
  set protocols ospf area 0 network '192.168.0.0/24'
  set protocols ospf area 0 network '10.1.1.1/32'
  set protocols ospf parameters opaque-lsa
  set protocols ospf parameters router-id '10.1.1.1'
  set protocols ospf segment-routing global-block high-label-value '1100'
  set protocols ospf segment-routing global-block low-label-value '1000'
  set protocols ospf segment-routing prefix 10.1.1.1/32 index explicit-null
  set protocols ospf segment-routing prefix 10.1.1.1/32 index value '1'

**Node 2**

.. code-block:: none

  set interfaces loopback lo address 10.1.1.2/32
  set interfaces ethernet eth0 address 192.168.0.2/24
  set protocols ospf area 0 network '192.168.0.0/24'
  set protocols ospf area 0 network '10.1.1.2/32'
  set protocols ospf parameters opaque-lsa
  set protocols ospf parameters router-id '10.1.1.2'
  set protocols ospf segment-routing global-block high-label-value '1100'
  set protocols ospf segment-routing global-block low-label-value '1000'
  set protocols ospf segment-routing prefix 10.1.1.2/32 index explicit-null
  set protocols ospf segment-routing prefix 10.1.1.2/32 index value '2'


This gives us MPLS segment routing enabled and labels for far end loopbacks:

.. code-block:: none

  Node-1@vyos:~$ show mpls table
   Inbound Label  Type       Nexthop      Outbound Label
   -----------------------------------------------------------
   1002           SR (OSPF)  192.168.0.2  IPv4 Explicit Null  <-- Node-2 loopback learned on Node-1
   15000          SR (OSPF)  192.168.0.2  implicit-null
   15001          SR (OSPF)  192.168.0.2  implicit-null

  Node-2@vyos:~$ show mpls table
   Inbound Label  Type       Nexthop      Outbound Label
   -----------------------------------------------------------
   1001           SR (OSPF)  192.168.0.1  IPv4 Explicit Null  <-- Node-1 loopback learned on Node-2
   15000          SR (OSPF)  192.168.0.1  implicit-null
   15001          SR (OSPF)  192.168.0.1  implicit-null

Here is the routing tables showing the MPLS segment routing label operations:

.. code-block:: none

  Node-1@vyos:~$ show ip route ospf
  Codes: K - kernel route, C - connected, S - static, R - RIP,
         O - OSPF, I - IS-IS, B - BGP, E - EIGRP, N - NHRP,
         T - Table, v - VNC, V - VNC-Direct, A - Babel, F - PBR,
         f - OpenFabric,
         > - selected route, * - FIB route, q - queued, r - rejected, b - backup
         t - trapped, o - offload failure

  O   10.1.1.1/32 [110/0] is directly connected, lo, weight 1, 00:03:43
  O>* 10.1.1.2/32 [110/1] via 192.168.0.2, eth0, label IPv4 Explicit Null, weight 1, 00:03:32
  O   192.168.0.0/24 [110/1] is directly connected, eth0, weight 1, 00:03:43

  Node-2@vyos:~$ show ip route ospf
  Codes: K - kernel route, C - connected, S - static, R - RIP,
         O - OSPF, I - IS-IS, B - BGP, E - EIGRP, N - NHRP,
         T - Table, v - VNC, V - VNC-Direct, A - Babel, F - PBR,
         f - OpenFabric,
         > - selected route, * - FIB route, q - queued, r - rejected, b - backup
         t - trapped, o - offload failure

  O>* 10.1.1.1/32 [110/1] via 192.168.0.1, eth0, label IPv4 Explicit Null, weight 1, 00:03:36
  O   10.1.1.2/32 [110/0] is directly connected, lo, weight 1, 00:03:51
  O   192.168.0.0/24 [110/1] is directly connected, eth0, weight 1, 00:03:51

**************************
Example with Cisco IOS-XR 
**************************

When utilizing VyOS in an environment with Cisco IOS-XR gear you can use this 
blue print as an initial setup to get MPLS ISIS-SR working between those two 
devices.The lab was build using :abbr:`EVE-NG (Emulated Virtual
Environment NG)`.

.. figure:: /_static/images/vyos-sr-isis.png
   :alt: ISIS-SR network

   ISIS-SR example network

The below configuration is used as example where we keep focus on 
VyOS-P1/VyOS-P2/XRv-P3 which we share the settings.


Configuration
=============

VyOS-P1:
========
.. code-block:: none

  set interfaces dummy dum0 address '192.0.2.1/32'
  set interfaces ethernet eth1 address '192.0.2.5/30'
  set interfaces ethernet eth1 mtu '8000'
  set interfaces ethernet eth3 address '192.0.2.21/30'
  set interfaces ethernet eth3 mtu '8000'
  set protocols isis interface dum0 passive
  set protocols isis interface eth1 network point-to-point
  set protocols isis interface eth3 network point-to-point
  set protocols isis level 'level-2'
  set protocols isis log-adjacency-changes
  set protocols isis metric-style 'wide'
  set protocols isis net '49.0000.0000.0000.0001.00'
  set protocols isis segment-routing maximum-label-depth '8'
  set protocols isis segment-routing prefix 192.0.2.1/32 index value '1'
  set protocols mpls interface 'eth1'
  set protocols mpls interface 'eth3'
  set system host-name 'P1-VyOS'

XRv-P3:
=======
.. code-block:: none

  hostname P3-VyOS
  interface Loopback0
   ipv4 address 192.0.2.3 255.255.255.255
  !
  interface GigabitEthernet0/0/0/1
   mtu 8014
   ipv4 address 192.0.2.6 255.255.255.252
  !
  interface GigabitEthernet0/0/0/2
   mtu 8014
   ipv4 address 192.0.2.18 255.255.255.252
  !
  router isis VyOS
   is-type level-2-only
   net 49.0000.0000.0000.0003.00
   log adjacency changes
   address-family ipv4 unicast
    metric-style wide
    segment-routing mpls
   !
   interface Loopback0
    passive
    address-family ipv4 unicast
     prefix-sid index 3
    !
   !
   interface GigabitEthernet0/0/0/1
    point-to-point
    address-family ipv4 unicast
    !
   !
   interface GigabitEthernet0/0/0/2
    point-to-point
    address-family ipv4 unicast
    !
   !
  !

VyOS-P2:
========
.. code-block:: none
  
  set interfaces dummy dum0 address '192.0.2.2/32'
  set interfaces ethernet eth2 address '192.0.2.17/30'
  set interfaces ethernet eth2 mtu '8000'
  set interfaces ethernet eth3 address '192.0.2.26/30'
  set interfaces ethernet eth3 mtu '8000'
  set protocols isis interface dum0 passive
  set protocols isis interface eth2 network point-to-point
  set protocols isis interface eth3 network point-to-point
  set protocols isis level 'level-2'
  set protocols isis log-adjacency-changes
  set protocols isis metric-style 'wide'
  set protocols isis net '49.0000.0000.0000.0002.00'
  set protocols isis segment-routing maximum-label-depth '8'
  set protocols isis segment-routing prefix 192.0.2.2/32 index value '2'
  set protocols mpls interface 'eth2'
  set protocols mpls interface 'eth3'
  set system host-name 'P2-VyOS'

This gives us MPLS segment routing enabled and labels forwarding :

.. code-block:: none
  
   vyos@P1-VyOS:~$ show mpls table
   Inbound Label  Type        Nexthop               Outbound Label
   -----------------------------------------------------------------
   15000          SR (IS-IS)  192.0.2.6             implicit-null
   15001          SR (IS-IS)  192.0.2.22            implicit-null
   15002          SR (IS-IS)  fe80::5200:ff:fe04:3  implicit-null
   16002          SR (IS-IS)  192.0.2.6             16002
   16003          SR (IS-IS)  192.0.2.6             implicit-null
   16011          SR (IS-IS)  192.0.2.22            implicit-null
  
   vyos@P2-VyOS:~$ show mpls table
   Inbound Label  Type        Nexthop     Outbound Label
   -------------------------------------------------------
   15000          SR (IS-IS)  192.0.2.18  implicit-null
   16001          SR (IS-IS)  192.0.2.18  16001
   16003          SR (IS-IS)  192.0.2.18  implicit-null
   16011          SR (IS-IS)  192.0.2.18  16011

   RP/0/0/CPU0:P3-VyOS#show mpls forwarding
   Tue Mar 28 17:47:18.928 UTC
   Local  Outgoing    Prefix             Outgoing     Next Hop        Bytes
   Label  Label       or ID              Interface                    Switched
   ------ ----------- ------------------ ------------ --------------- ------------
   16001  Pop         SR Pfx (idx 1)     Gi0/0/0/1    192.0.2.5       0
   16002  Pop         SR Pfx (idx 2)     Gi0/0/0/2    192.0.2.17      0
   16011  16011       SR Pfx (idx 11)    Gi0/0/0/1    192.0.2.5       0
   24000  Pop         SR Adj (idx 1)     Gi0/0/0/1    192.0.2.5       0
   24001  Pop         SR Adj (idx 3)     Gi0/0/0/1    192.0.2.5       0
   24002  Pop         SR Adj (idx 1)     Gi0/0/0/2    192.0.2.17      0
   24003  Pop         SR Adj (idx 3)     Gi0/0/0/2    192.0.2.17      0


VyOS is able to check MSD per devices: 

.. code-block:: none

   vyos@P1-VyOS:~$ show isis segment-routing node
   Area VyOS:
   IS-IS L1 SR-Nodes:
  
   IS-IS L2 SR-Nodes:
  
   System ID       SRGB           SRLB            Algorithm  MSD
   ---------------------------------------------------------------
   0000.0000.0001  16000 - 23999  15000 - 15999   SPF        8
   0000.0000.0002  16000 - 23999  15000 - 15999   SPF        8
   0000.0000.0003  16000 - 23999  0 - 4294967295  SPF        10
   0000.0000.0011  16000 - 23999  15000 - 15999   SPF        8

   vyos@P2-VyOS:~$ show isis segment-routing node
   Area VyOS:
    IS-IS L1 SR-Nodes:
   
    IS-IS L2 SR-Nodes:
   
    System ID       SRGB           SRLB            Algorithm  MSD
    ---------------------------------------------------------------
    0000.0000.0001  16000 - 23999  15000 - 15999   SPF        8
    0000.0000.0002  16000 - 23999  15000 - 15999   SPF        8
    0000.0000.0003  16000 - 23999  0 - 4294967295  SPF        10
    0000.0000.0011  16000 - 23999  15000 - 15999   SPF        8

Here is the routing tables showing the MPLS segment routing label operations:

.. code-block:: none

   vyos@P1-VyOS:~$ show ip route isis
   Codes: K - kernel route, C - connected, S - static, R - RIP,
          O - OSPF, I - IS-IS, B - BGP, E - EIGRP, N - NHRP,
          T - Table, v - VNC, V - VNC-Direct, A - Babel, F - PBR,
          f - OpenFabric,
          > - selected route, * - FIB route, q - queued, r - rejected, b - backup
          t - trapped, o - offload failure
   
   I>* 192.0.2.2/32 [115/30] via 192.0.2.6, eth1, label 16002, weight 1, 1d03h18m
   I>* 192.0.2.3/32 [115/10] via 192.0.2.6, eth1, label implicit-null, weight 1, 1d03h18m
   I   192.0.2.4/30 [115/20] via 192.0.2.6, eth1 inactive, weight 1, 1d03h18m
   I>* 192.0.2.11/32 [115/20] via 192.0.2.22, eth3, label implicit-null, weight 1, 1d02h47m
   I>* 192.0.2.16/30 [115/20] via 192.0.2.6, eth1, weight 1, 1d03h18m
   I   192.0.2.20/30 [115/20] via 192.0.2.22, eth3 inactive, weight 1, 1d02h48m
   I>* 192.0.2.24/30 [115/30] via 192.0.2.6, eth1, weight 1, 1d03h18m
   
   
   vyos@P2-VyOS:~$ show ip route isis
   Codes: K - kernel route, C - connected, S - static, R - RIP,
          O - OSPF, I - IS-IS, B - BGP, E - EIGRP, N - NHRP,
          T - Table, v - VNC, V - VNC-Direct, A - Babel, F - PBR,
          f - OpenFabric,
          > - selected route, * - FIB route, q - queued, r - rejected, b - backup
          t - trapped, o - offload failure
   
   I>* 192.0.2.1/32 [115/30] via 192.0.2.18, eth2, label 16001, weight 1, 1d03h17m
   I>* 192.0.2.3/32 [115/10] via 192.0.2.18, eth2, label implicit-null, weight 1, 1d03h17m
   I>* 192.0.2.4/30 [115/20] via 192.0.2.18, eth2, weight 1, 1d03h17m
   I>* 192.0.2.11/32 [115/40] via 192.0.2.18, eth2, label 16011, weight 1, 1d02h47m
   I   192.0.2.16/30 [115/20] via 192.0.2.18, eth2 inactive, weight 1, 1d03h17m
   I>* 192.0.2.20/30 [115/30] via 192.0.2.18, eth2, weight 1, 1d03h17m
   
   RP/0/0/CPU0:P3-VyOS#show route isis
   Tue Mar 28 18:19:16.417 UTC
   
   i L2 192.0.2.1/32 [115/20] via 192.0.2.5, 1d03h, GigabitEthernet0/0/0/1
   i L2 192.0.2.2/32 [115/20] via 192.0.2.17, 1d03h, GigabitEthernet0/0/0/2
   i L2 192.0.2.11/32 [115/30] via 192.0.2.5, 1d02h, GigabitEthernet0/0/0/1
   i L2 192.0.2.20/30 [115/20] via 192.0.2.5, 1d03h, GigabitEthernet0/0/0/1
   i L2 192.0.2.24/30 [115/20] via 192.0.2.17, 1d03h, GigabitEthernet0/0/0/2

Ping between VyOS-P1 / VyOS-P2 to confirm reachability:

.. code-block:: none

   vyos@P1-VyOS:~$ ping 192.0.2.2 source-address 192.0.2.1
   PING 192.0.2.2 (192.0.2.2) from 192.0.2.1 : 56(84) bytes of data.
   64 bytes from 192.0.2.2: icmp_seq=1 ttl=63 time=3.47 ms
   64 bytes from 192.0.2.2: icmp_seq=2 ttl=63 time=2.06 ms
   64 bytes from 192.0.2.2: icmp_seq=3 ttl=63 time=3.90 ms
   64 bytes from 192.0.2.2: icmp_seq=4 ttl=63 time=3.87 ms
   ^C
   --- 192.0.2.2 ping statistics ---
   4 packets transmitted, 4 received, 0% packet loss, time 3004ms
   rtt min/avg/max/mdev = 2.064/3.326/3.903/0.748 ms

   vyos@P2-VyOS:~$ ping 192.0.2.1 source-address 192.0.2.2
   PING 192.0.2.1 (192.0.2.1) from 192.0.2.2 : 56(84) bytes of data.
   64 bytes from 192.0.2.1: icmp_seq=1 ttl=63 time=2.91 ms
   64 bytes from 192.0.2.1: icmp_seq=2 ttl=63 time=3.23 ms
   64 bytes from 192.0.2.1: icmp_seq=3 ttl=63 time=2.91 ms
   64 bytes from 192.0.2.1: icmp_seq=4 ttl=63 time=2.85 ms
   ^C
   --- 192.0.2.1 ping statistics ---
   4 packets transmitted, 4 received, 0% packet loss, time 3005ms
   rtt min/avg/max/mdev = 2.846/2.972/3.231/0.151 ms