Cisco Cisco ASR 5000 Administrator's Guide

 

▄  Cisco ASR 5x00 Home eNodeB Gateway Administration Guide 

This section describes the supported interfaces and Cisco supported deployment scenario of HeNB-GW in LTE access 
network. 

As mentioned above in the section “Deployment Scenarios for HeNB Access Network”, Cisco’s LTE Femtocell 
network solution focuses on Variant 1 where HeNB-GW is mandatory for HeNBs to connect. HeNB-GW may also be 
frequently deployed or co-located together with MME and/or S-GW/P-GW in the same system.  

These collocations are not yet supported in the Cisco ASR5x00 chassis and are planned for future releases. 

This section provides the brief information on supported interfaces on HeNB-GW node. 

In support of both mobile and network originated subscriber UE contexts, the HeNB-GW provides the following 
network interface support: 

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E-UTRAN Uu Interface: The LTE Uu interface is responsible for all sort of signalling between UE and 

eNodeB. It carries all signalling message between the eNodeB and the MME along with the user traffic 
between the eNodeB and S-GW. This way the Uu interface works over both the Control as well as User planes. 

 The protocols of the LTE Uu interface include: 



 

Radio Resource Control (RRC): This protocol governs the signalling between the UE and MME. 

Technically, the RRC governing lies between the UE and eNodeB. It terminates on the RAN access 
equipment and then signalling is forwarded to MME. 



 

Non-Access Stratum (NAS): This protocol also governs the signalling between UE and MME  

Other than the above protocols, both the control planes (Control and User) of the Uu interface are supported by 
the same set of interface functions. These interface functions include Security and Header Compression. All of 
these functions are carried by the physical layer over the air as shown in the following figure: