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16

RSSI is a Radio-Frequency (RF) term and stands for Received Signal Strength Indicator. It is a measure of the power level that a RF device, such as WiFi or 3G client, is receiving from the radio infrastructure at a given location and time. For instance, the power level a laptop is detecting from a nearby AP. Usually, the higher the RSSI the better the ...


14

The closer the figure is to zero, the better. So in the figures you've given above, -75 is better than -100. In my experience -75 provide a reasonable service. -85 provides an OK service. -100 provides a barely usable service. -110 provides no service at all. This figure represents your signal strength to the cellular tower. The closer you are to a tower, ...


12

Cisco provides a special application for iphone devices or for android devices. Unfortunately Windows Phone isn't supported yet.


11

In this scenario, your phone has at least two network interfaces: WLAN and 3G. Each interface has his own IP address and mask. They usually install as two routes on the phones routing table, the locally connected network and a default gateway. Let's see a simplified example: Interface: Wifi IP/mask: 192.168.10.10 255.255.255.0 Default gateway: 192.168.10....


6

GSM data networks (GPRS, LTE etc) allocate IP addresses to end devices (Mobile Phones) just like any other network. As to whether NAT/PAT is used, this is entirely carrier dependent - based on a factor of how big their subscriber base is and how many public IPv4 addresses they have available. In Australia, the incumbent telco Telstra uses a CGN (carrier-...


5

Most 3G authentication will be done via PPP using either CHAP or PAP, so I'd start with: debug ppp negotiation debug ppp authentication and see what you get back.


5

Difficult to tell because it depends on the CDR, but in general, a data session in a mobile network refers to a "PDP context". A PDP context is the state kept for a user in the SGSN and GGSN (in a 3G network) and down to the UA (your phone) via RNCs and the NodeBs ("base stations"). The actual protocol used between GGSN and SGSN is a GTP tunnel while from ...


5

The other answer deals well with how the outbound traffic from your device decides which network connection to use. However it seems your question is asking more about how data inbound to your phone (such as push notifications) decides which network to use. There are a number of ways this is done, but if it is truly a service that works on both WiFi and ...


5

The primary point of IPv6 is that it restores the original idea of every device having a unique IP address, which restores the end-to-end concept of IP. NAT is a kludge to extend the life of IPv4 until IPv6 can become ubiquitous. The point of a VPN (Virtual Private Network) is to give your traffic privacy while in transit, although it can fix some of the ...


5

I think it's always best to allow end-user traffic to use an MTU of 1500. Therefore when encapsulated the overlay network has to cater for this either by a larger MTU size in the encapsulated domain or by fragmentation/reassembly techniques. Since fragmentation is computationally expensive when performed in software, I believe that a service provider ...


5

The Cell Phone get a Private IP address.They will do NAT as the packet leave out the Operator's network. They use Layer 2 PPP protocol to negotiate the IP for UEs. Ifconfig output from my Mobile:


4

It turns out the database I was working with was incomplete. I was using "python-netaddr" on Ubuntu 14.04, and this was significantly smaller than the Wireshark combined IEEE+misc database. After I fixed this, all but a very few MACs had valid vendors, which is the result I was expecting.


4

Yes, there is a reason to it. Be advised that even if the 3GDT is set up between RNC and GGSN, the "2G non home public" users , ie "2G roamer users" only use IuPS on your picture, and don't use 3GDT. We both know that 2G users can access 3G Core network depending on the policy of authorization mode based on IMSI or based on algorithm mode in SGSN. The ...


4

AFAIK RSSI is arbitrary (and of questionable use) unit, but at least my 3G cisco actually outputs dBm: bu.ip.fi#show cellular 0 radio Radio power mode = ON Current Band = WCDMA 2100, Channel Number = 10737 Current RSSI = -64 dBm Band Selected = Auto Number of nearby cells = 1 Cell 1 Primary Scrambling Code = 0x14A RSCP = -64 dBm, ECIO = -4 dBm dBm ...


4

LTE is a standard for building a mobile network. It lists the available bands on which to operate on and Band 4 is one of those bands. See https://en.wikipedia.org/wiki/E-UTRA#Frequency_bands_and_channel_bandwidths for a full list. If someone mentions only "LTE" than the band is not specified but you can look up which bands are in used by a specific ...


4

Do wireless devices such as smartphones transmit beacon equivalent frames such as APs do? A wireless client does not transmit beacon frames. However if a device is configured to provide service (i.e. tethering, etc), then it is acting as an access point and would transmit beacons. Can they be made to announce their presence somehow using layer 2 frames ...


4

Short answer: This is not going to work. Depending where you live, there are regulations that specify the transmitter power and antenna type (gain). This varies with the frequency band you are using (2.4GHz vs 5 GHz). Remember that WiFi is two-way communication. Not only does your AP have to have a strong enough signal for your clients to hear it, but ...


4

If you have access to 10 layer 3 switches you can certainly make this work. Treat each trailer as if it is a campus building with local internet. choose the trailer with the NAS as the core of the network and wire up each trailer to that core switch. Wire each switch in the trailer to the LTE router and create a static default route to the specific LTE ...


4

An IP address is an IP address, and there is nothing in IP that distinguishes what you are looking for. There is the IANA IPv4 Special-Purpose Address Registry that explains all the special-purpose IPv4 address ranges, and IANA IPv6 Special-Purpose Address Registry for IPv6. IP really doesn't care about what the host is, only that it is addressed in order to ...


3

In my opinion, S-GW is not required as part of full MVNO LTE architecture. Because, in principle, the S-GW needs to connect to all the LTE Radio Network Coverage (eNodeB) and unfortunately, generally, a MVNO does not have such LTE Radio Network, that's why he is a MVNO. But if the full MVNO want to have a S-GW anyway, he can, but he will need to ...


3

It is possible to take calls from any location because, the mobile phone keeps the network/cellular operator informed about its location. This in-turn enables the mobile operator to route the calls to you anywhere. HLR is the most important database maintained by the operator. The subscriber info is created by the operator in HLR at the time of purchase of ...


3

IMEI is provided by equipment manufacturer for the mobile. It is stored in EIR via the network operator while registration. IMSI is a combination of MCC(Mobile country code), MNC(Mobile Network code) , MSIN(Mobile subscriber Identification number) and is stored in SIM. There are several such identifiers based on the mode of operation to uniquely identify a ...


3

Very likely, yes, as it's not the same protocol as 802.11a (even if you could get the 5ghz radio onto the right band)


3

It depends - sometimes the MNO will simply hand off at layer 3 from its own PGW to the MVNO's PDN. Sometimes the MVNO is completely virtual and has no physical network of its own. In other instances the MVNO might have its own UMTS/LTE network, in which case the MNO will hand off from its SGW to the MVNO's PGW (if I'm remembering my LTE architecture ...


3

In theory the TMA can be mounted near the BTS, but you risk that the signal is attenuated too much by the cable. Also most BTS have a amplifier built in, which makes a TMA mounted next to it redundant. As the name Tower Mounted Amplifier implies, the whole point is to amplify the signal as close to the source as possible. See http://en.wikipedia.org/wiki/...


3

802.11 specifies clients listen for AP beacons. They don't broadcast anything. However, real world implementations (Windows, iOS, etc.) actively hunt for known SSIDs when they aren't associated. These probes will broadcast a MAC, but in the case of recent-ish iOS, Apple randomizes the MAC for these probes. (to thwart attempts at passive tracking)


3

While it can work using highly directional antennas (which increase both transmission and reception at the AP for devices in the correct spatial region relative to the antenna, compensating for the limited antenna and output of the mobile device while staying in legal limits for EIRP) your "illustration" would appear to show a situation where it's unlikely ...


3

I'd love to be corrected, but I believe that MobileIP was stillborn. There's a paper here from a researcher at Rutgers that summarizes the situation. The problem it was trying to solve - splitting the use of an IPv4 address as an endpoint identifier and a routing label - became less important once the (mobile) community embraced IPv6.


3

I think your idea that consumer and mobile ISPs will give out static IPv6 is optimistic to say the least. Some may do so but many probably will not. VPNs provide two main features. They provide protection for the traffic against evesdropping, spoofing, replay attacks and so-on. They decouple your addressing and routing from the operators of your underlying ...


3

IS-41 is a protocol used to manage many aspects of mobile (as in cellular phone) networks. When someone places a call (or sends a text message or IP packet) to a subscriber of a mobile network, the mobile network needs to find out where the subscriber's phone (usually referred to as User Equipment, or UE) is located in order to deliver the call to the ...


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