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Where ever I check for build.prop tweaks to enhance 3g or wifi connectivity I see this tweak , can anyone explain what these values are exactly?

what is "ro.ril.hep" means ?

why given the value 0 for it ?

can anybody explain the below given tweaks ?

# RIL settings
ro.ril.hep=0
ro.ril.hsxpa=2
ro.ril.gprsclass=12
ro.ril.enable.dtm=1
ro.ril.hsdpa.category=8
ro.ril.enable.a53=1
ro.ril.enable.3g.prefix=1
ro.ril.htcmaskw1.bitmask=4294967295
ro.ril.htcmaskw1=14449
ro.ril.hsupa.category=6

# net speed tweaks:
net.tcp.buffersize.default=4096,87380,256960,4096, 16384,256960
net.tcp.buffersize.wifi=4096,87380,256960,4096,163 84,256960
net.tcp.buffersize.umts=4096,87380,256960,4096,163 84,256960
net.tcp.buffersize.gprs=4096,87380,256960,4096,163 84,256960
net.tcp.buffersize.edge=4096,87380,256960,4096,163 84,256960
net.tcp.buffersize.hspda=4096,87380,256960,4096,16 384,256960
net.tcp.buffersize.hspa=4096,87380,256960,4096,163 84,256960

# Wireless Tweaks:
net.ipv4.ip_no_pmtu_disc=0
net.ipv4.route.flush=1
net.ipv4.tcp_ecn=0
net.ipv4.tcp_fack=1
net.ipv4.tcp_mem=187000 187000 187000
net.ipv4.tcp_moderate_rcvbuf=1
net.ipv4.tcp_no_metrics_save=1
net.ipv4.tcp_rfc1337=1
net.ipv4.tcp_rmem=4096 39000 187000
net.ipv4.tcp_sack=1
net.ipv4.tcp_timestamps=1
net.ipv4.tcp_window_scaling=1
net.ipv4.tcp_wmem=4096 39000 187000
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Parts of those build.prop tweaks (and several you did not mention) are explained in the attachments to this XDA post. Let's see what of yours is covered – which are mostly the RIL settings (Radio Interface Layer):

  • ro.ril.hep : unknown and undefined … may not even exist
  • ro.ril.hsxpa : 1:HSDPA, 2:HSDPA/HSUPA, 3:? (HSUPA only?)
  • ro.ril.gprsclass : see: GPRS classes
  • ro.ril.enable.dtm : Dual Transfer Mode. Only set this to 1 if your network allows simultaneous transfer of Circuit switched (CS) voice and Packet switched (PS) data over the same radio channel (ARFCN)
  • ro.ril.hsdpa.category : HSDPA speed class; e.g. 21 = 23.4 MBit/s
  • ro.ril.hsupa.category : dito for HSUPA; 6 = 5.76 MBit/s
  • ro.ril.enable.a53 : gprs encryption algorithm; "may not even exist"
  • ro.ril.enable.3g.prefix : show "3g" on lock screen next to network name
  • ro.ril.htcmaskw1.bitmask : (not there; maybe HTC specific?)
  • net speed tweaks: (not documented there)1
  • wireless tweaks: (not documented there)2

1: also see What range of tcp buffer size do you suggest for slow and fast networks? and TCP buffers - smaller can actually be BETTER!. By the latter, the values here stand for "ReadMin, ReadInitial, Readmax, WriteMin, WriteInitial, WriteMax".

2:

  • net.ipv4.ip_no_pmtu_disc: "Set this if you want to disable Path MTU discovery - a technique to determine the largest Maximum Transfer Unit possible on your path." (Source)
  • net.ipv4.tcp_mem: "The tcp_mem variable defines how the TCP stack should behave when it comes to memory usage. ... The first value specified in the tcp_mem variable tells the kernel the low threshold. Below this point, the TCP stack do not bother at all about putting any pressure on the memory usage by different TCP sockets. ... The second value tells the kernel at which point to start pressuring memory usage down. ... The final value tells the kernel how many memory pages it may use maximally. If this value is reached, TCP streams and packets start getting dropped until we reach a lower memory usage again. This value includes all TCP sockets currently in use." (source: Network / TCP / UDP Tuning)

I won't explain all the TCP settings here (they are not Android specific, so this doesn't really belong here). You can find most of the missing settings at Obscure Settings.

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  • 1
    PS, disclosure: linked "XDA-post with attachment" is mine. Took me half a day of research to figure most of them ;)
    – Izzy
    Jul 14 '15 at 12:39
  • +1 (did an hour ago); Thanks for the disclosure, I definitely missed it. :)
    – Firelord
    Jul 14 '15 at 14:13
  • @Firelord yeah, I first thought it obvious enough – but then remembered my user-names slightly differ between the sites ("Izzy" was already taken/not available when I was joining XDA)
    – Izzy
    Jul 14 '15 at 14:30

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