Stefano

I like your idea of treating femtocells by adding a new subsection.

Note that while the Iuh interface indeed has important security considerations,
the Iub interface is also almost always encrypted. In any case, the important 
issue
here is to note the security requirements.

The middlebox issue is an important one, which needs to be noted.

There will also be different scalability concerns, as a FGW needs to handle
many more femtocells than an RNC needs to handle NodeBs.

Y(J)S

From: Stefano Ruffini [mailto:[email protected]]
Sent: Friday, August 28, 2009 14:21
To: Yaakov Stein; [email protected]
Subject: RE: [TICTOC] FW: Adding the Femto Synchronization requirments in 
requirement document

Hi Yaakov,

I would suggests few updates to your proposals also based on some comments that 
were made in Stockholm on this subject:

1. The femtocells application can be based on one of the technologies already 
mentioned in 3.1.1 (and in fact the 250 ppb requirement which is related to 
home base stations, which is the way 3GPP calls the femtocell,  is already 
mentioned in this section).
 In order to avoid misunderstanding,  the new section  could be called 3.1.2, 
"Specific aspects related to Femtocells application".
Some rephrasing in the introductory text might also be needed (e.g. remove 
"presented in Section 3.1.1.x " as scenarios that assume private network).
The Notes related to "Private Networks" could be updated as follows:
Note 2: assumes a private network, (this may not be true in case of femtocells)

2. The first point on IPSEC is based on still quite vague considerations (no 
real study or test has been presented on this topic showing the actual 
degradation). I would suggest to be more generic ,  for instance saying that 
the impacts on performances due to IPSEC are under study.

3. Regarding alternative solution to IPSEC perhaps rather than refer to "secure 
links" (which in case needs to be clarified), it seems more appropriate to 
refer to existing solutions (e.g. built in authentication)

The above comments would results in updating the text as follows:
"

3.1 Cellular Backhauling
...
3.1.1 Cellular Backhauling Requirements
.....

3.1.2 Specific aspects related to the Femtocells application

Femtocell application may use a portion of the public and private network 
infrastructure to provide connectivity and backhaul service between the 
femtocell device and gateway. The use of a public network facility implies that 
some level of network security is necessary, as compared to the scenarios which 
assume that the connectivity and backhaul service is done over a private 
network (eg., see Note (2)), typically for macrocell application. In addition 
the number of femtocell devices can easily extend to hundreds of thousands, 
much higher than the number of macrocells. The following requirements should be 
considered for femtocell deployments:


 1.  The impact of the use of IPSec links in the public network on the 
transport of synchronization message and its performance is under study. 
Alternative means to guarantee that timing messages are securely delivered to 
the femtocells base stations might be considered (e.g. built in authentication).
 2.  Synchronization messages traversing Network Address Translation (NAT) 
functions need to be considered in order to guarantee proper connectivity 
between a Clock Server and the femtocell device
 3.  Scalability aspects (large number of femtocells), bandwidth consumption of 
synchronization messages and the placement of clock servers are to be 
considered as the network architecture is developed.

3.1.3 Cellular Backhaul Requirements Summary
...
"

Best Regards
Stefano

________________________________
From: [email protected] [mailto:[email protected]] On Behalf Of 
Yaakov Stein
Sent: mercoledì 26 agosto 2009 13.37
To: [email protected]
Subject: [TICTOC] FW: Adding the Femto Synchronization requirments in 
requirement document
From: Xie Lei<mailto:[email protected]>
To: [email protected]<mailto:[email protected]>
Sent: Wednesday, August 26, 2009 9:50 AM
Subject: [TICTOC] Adding the Femto Synchronization requirments in requirement 
document


Dear All
As the agreement in IETF75# meeting, we decide to add the femto synchronization 
requirements in requirement document. After checking the requirement document, 
i think, the best way is to add a new section as following:


3.2.1 Cellular Backhauling of Femtocells

Femtocell application may use a portion of the public and private network 
infrastructure to provide connectivity and backhaul service between the 
femtocell device and gateway. The use of a public network facility implies that 
some level of network security is necessary, as compared to the scenarios 
presented in Section 3.1.1.x which assumed that the connectivity and backhaul 
service is done over a private network (eg., see Note (2)), typically for 
macrocell application. In addition the number of femtocell devices can easily 
extend to hundreds of thousands, much higher than the number of macrocells. The 
following requirements should be considered for femtocell deployments:


 1.  The use of IPSec links in the public network could degrade the transport 
of synchronization message and its performance. In order to reduce the impact 
to synchronization when traversing secured links, it is possible to leave some 
of the synchronization message unprotected. Caution should take place on the 
use of IPSec and synchronization performance
 2.  Synchronization messages traversing Network Address Translation (NAT) 
functions need to be considered in order to guarantee proper connectivity 
between a Clock Server and the femtocell device
 3.  Scalability aspects (large number of femtocells), bandwidth consumption of 
synchronization messages and the placement of clock servers are to be 
considered as the network architecture is developed.
Please give your comments on these words, Thanks

Best Regards
Rock
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