ESR Series Routers Operation Manual                                                          7 
2  PRODUCT DESCRIPTION 
2.1  Purpose 
ESR  series  devices  are  the  high  performance  multi-purpose  network  routers.    Device  combines 
traditional network features with a complex multi-tier approach to routing security, and ensures robust 
corporate environment protection.  
Device  has  a  built-in  firewall  that  enables  protection  of  your  network  environment  and  supports 
latest data security, encryption, authentication and anti-intrusion features. 
Device  contains  software  and  hardware  means  of  data  processing.  Top  performance  is  achieved 
through optimal distribution of data processing tasks between different subsets of the device. 
2.2  Functions 
2.2.1  Interface functions 
Table 2.1 lists interface functions of the device. 
Table 2.1 – Device interface functions  
Cable connection 
polarity detection 
(Auto MDI/MDIX) 
Automatic cable type detection—crossed or straight.  
–  MDI (Media-Dependent Interface—straight)—cable standard for 
connection of terminal devices  
–  MDIX (Media-Dependent Interface with Crossover—crossed)—cable 
standard for connection of hubs and switches 
Backpressure routing 
support 
(Back pressure) 
The backpressure routing method is utilized in half-duplex connections for 
management of data streams, coming from the opposite devices, by means of 
collisions. This method allows to avoid buffer overruns and the loss of data.  
Flow control 
(IEEE 802.3X) 
Flow control allows to interconnect the low-speed and the high-speed devices. To 
avoid buffer overrun, the low-speed device gains the ability to send PAUSE 
packets, that will force the high-speed device to pause the packet transmission. 
Link aggregation allows to increase the communication link bandwidth and 
robustness. 
Router supports static and dynamic link aggregation. For dynamic aggregation, link 
group management is performed via LACP protocol.