Re: [Detnet] Crosshaul input for consideration in draft-ietf-detnet-use-cases

[Balázs Varga A <[e-mail]>]

Hi Carlos,



Some comments and a question for clarification:



6.1.4.  Transport Loss Constraints

> Some fronthaul functional splits considered by 3GPP require the frame loss ratio (FLR)

> to be less than 10E-7 for data traffic and less than 10E-6 for C&M.

Functional split is still under heavy discussion in 3GPP. These numbers are not defined by 3GPP

and may be dependent on discussion results. So I think including them in the use-case draft

may causes confusions.



6.3.  Cellular Radio Networks Future

> o  Different splits of the functionality run on the base stations

>    (baseband processing units) and the remote radio heads (antennae)

>    could co-exist on the same Fronthaul and Backhaul network.

I see a terminology issue here mainly due to the fact that future splits and the resulting

network elements are not (yet) defined. Baseband processing units and antenna refers

to legacy technologies, which does not require DetNet and are out-of-scope.



6.4.  Cellular Radio Networks Asks

> new proposed bullets …

Do You propose to extend this section with general requirements of the Cellular

Radio Networks? This section focuses on “data plane transport”. I have concerns on

some items of your list and have found some of them not relevant from DetNet

perspective.



Cheers

Bala’zs





-----Original Message-----
From: Carlos Jesús Bernardos Cano [mailto:[e-mail]]
Sent: Friday, March 10, 2017 2:22 AM
To: [e-mail]
Cc: [e-mail]
Subject: Crosshaul input for consideration in draft-ietf-detnet-use-cases



Hi,



In Seoul we presented draft-bernardos-detnet-crosshaul-requirements-

00.txt as potential input to be considered for "Section 6. Cellular radio" of draft-ietf-detnet-use-cases. The group agreed that contributions from us were welcome to complement/fix the text in the use cases document.



We have taken -11 version and tried to propose specific changes to the document. Please find them below for discussion.



----

6.1.1.  Network Architecture



OLD:



Figure 10 illustrates a typical 3GPP-defined cellular network architecture, which includes "Fronthaul" and "Midhaul" network segments.  The "Fronthaul" is the network connecting base stations (baseband processing units) to the remote radio heads (antennas).

The "Midhaul" is the network inter-connecting base stations (or small cell sites).



NEW:



Figure 10 illustrates a typical 3GPP-defined cellular network architecture, which includes "Fronthaul", "Midhaul" and "Backhaul"

network segments.  The "Fronthaul" is the network connecting base stations (baseband processing units) to the remote radio heads (antennas).  The "Midhaul" is the network inter-connecting base stations (or small cell sites).  The "Backhaul" is the network or links connecting the radio base station sites to the network controller/gateway sites (i.e. the core of the 3GPP cellular network).

----

6.1.3.  Time Synchronization Constraints



[...]



OLD:



In cellular networks from the LTE radio era onward, phase synchronization is needed in addition to frequency synchronization ([TS36300], [TS23401]).



NEW:



In cellular networks from the LTE radio era onward, phase synchronizatio n is needed in addition to frequency synchronization ([TS36300], [TS23401]).



Time constraints are also important due to its impact on packet loss.

If a packet is delivered too late, then the packet may be dropped by the host.

----



----

6.1.4.  Transport Loss Constraints



[...]



OLD:



For packetized Fronthaul and Midhaul connections packet loss may be caused by BER, congestion, or network failure scenarios.  Current tools for elminating packet loss for Fronthaul and Midhaul networks have serious challenges, for example retransmitting lost packets and/ or using forward error correction (FEC) to circumvent bit errors is practically impossible due to the additional delay incurred.  Using redundant streams for better guarantees for delivery is also practically impossible in many cases due to high bandwidth requirements of Fronthaul and Midhaul networks.  Protection switching is also a candidate but current technologies for the path switch are too slow to avoid reset of mobile interfaces.



NEW:



For packetized Fronthaul and Midhaul connections packet loss may be caused by BER, congestion, or network failure scenarios.  Some fronthaul functional splits considered by 3GPP require the frame loss ratio (FLR) to be less than 10E-7 for data traffic and less than

10E-6 for C&M.  Current tools for eliminating packet loss for Fronthaul and Midhaul networks have serious challenges, for example retransmitting lost packets and/or using forward error correction

(FEC) to circumvent bit errors is practically impossible due to the additional delay incurred.  Using redundant streams for better guarantees for delivery is also practically impossible in many cases due to high bandwidth requirements of Fronthaul and Midhaul networks.

Protection switching is also a candidate but current technologies for the path switch are too slow to avoid reset of mobile interfaces.

----



----

6.3.  Cellular Radio Networks Future



[...]



OLD:



o  All form of xHaul networks will need some form of DetNet

  solutions.  For example with the advent of 5G some Backhaul

   traffic will also have DetNet requirements (e.g. traffic belonging

   to time-critical 5G applications).



NEW:



o  All form of xHaul networks will need some form of DetNet

   solutions.  For example with the advent of 5G some Backhaul

   traffic will also have DetNet requirements (e.g. traffic belonging

   to time-critical 5G applications).



o  Different splits of the functionality run on the base stations

   (baseband processing units) and the remote radio heads (antennae)

   could co-exist on the same Fronthaul and Backhaul network.

----



----

6.4.  Cellular Radio Networks Asks



[...]



OLD:



A standard for data plane transport specification which is:



o  Unified among all xHauls (meaning that different flows with

   diverse DetNet requirements can coexist in the same network and

   traverse the same nodes without interfering with each other)



o  Deployed in a highly deterministic network environment



NEW:



A standard for data plane transport specification which is:



o  Unified among all xHauls (meaning that different flows with

   diverse DetNet requirements can coexist in the same network and

   traverse the same nodes without interfering with each other)



o  Deployed in a highly deterministic network environment



o  Capable of supporting multiple functional splits simultaneously,

   including existing Backhaul and CPRI Fronthaul and new modes as

   defined for example in 3GPP.



o  Slicing and Multi-tenancy-capable, supporting: isolating traffic

   (guaranteed QoS) and separating traffic (privacy).



o  Compatible with existing security and synchronization mechanisms,

   such as IEEE1588, IEEE802.1AS.



o  Capable of transporting both in-band and out-band control traffic

   (OAM info, ...).



o  Deployable over multiple data link technologies (e.g., IEEE 802.3,

   mmWave, etc.).

----



Comments are welcome,



Thanks,



Carlos