10   ESR Series Routers Operation Manual 
2.2.5  Traffic tunnelling functions 
Table 2.5 —Traffic tunnelling functions 
Tunnelling  is  a  method  of  packet  conversion  during  their  network  transfer  that 
involves  the  replacement,  modification  and  addition  of  a  new  packet  network 
header. This method may be used for negotiation of transport protocols when the 
data is transferred through the transit network as well as for creation of secured 
connections where tunnelled data is being encrypted. 
Routers support the following types of tunnels: 
–  GRE—IP packet is encapsulated into another IP packet with GRE (General 
Routing Encapsulation) header 
–  IPv4-IPv4—tunnel that encapsulates source IP packets into IP packets 
with alternative network parameters 
–  L2TPv3—tunnel for L2 traffic transmission using IP packets 
–  IPsec—tunnel with the encryption of transmitted data 
–  L2TP, PPTP—tunnels used for establishing a remote 'client-sever' access 
2.2.6  Management and configuration functions 
Table 2.6 —Basic management and configuration functions  
Configuration file 
download and upload 
Device parameters are saved into the configuration file that contains configuration 
data  for  the  specific  device  ports  as  well  as  for  the  whole  system.  The  following 
protocols may be used for file transfers: TFTP, FTP, and SCP. 
Command line interface 
(CLI) 
CLI management is performed locally via serial port RS-232, or remotely via Telnet, 
SSH.  Console  command  line  interface  (CLI)  is  the  industrial  standard.  CLI 
interpreter contains the list of commands and keywords that will help the user and 
reduce the amount of input data. 
Syslog protocol is designed for transmission of system event messages and event 
logging. 
Network utilities:  
ping, traceroute 
ping and traceroute utilities allow you to check the availability of network devices 
and identify data transfer routes in IP networks. 
Controlled access 
management—
privilege levels 
Routers support system access level management for users. Access levels enable 
responsibility  areas  management  for  device  administrators.  Access  levels  are 
numbered  from  1  to  15;  Level  15  stands  for  full  access  to  device  management 
features. 
Authentication is a user identity check procedure. Routers support the following 
authentication methods: 
–  local—local user database stored on the device is used for authentication 
–  group—user database is located on the authentication server RADIUS 
and TACACS protocols are user for server interactions. 
SSH and Telnet server features allow you to establish connection to the device 
and perform device management.  
Automatic 
configuration restore 
Device features automatic configuration restore system designed to prevent 
remote access loss after re-configuration. If the configuration change is not 
confirmed in the defined time, configuration will be rolled back to the last known 
state.