Selection of Frequency Band & Implementation Wireless In

Selection of Frequency Band & Implementation Wireless In

For those who've never tried to implement wireless, will usually encounter some obstacles that sometimes confuse. However, current wireless technologies are widely applied, especially with the range of reasons. Wireless technology is quite helpful especially to reach areas far / wide. Instead of having to build a network cable to connect remote devices, it will be easier and more efficient if you use wireless. But behind these advantages, there are factors that make the application of wireless is not as easy as using a cable. When using a cable, we stayed plug from one port to another. If the remote could use a Fiber Optic. But when implementing a wireless, connect one device to another will be influenced by many factors. Among other things, LoS (Line of sight), site 1 to site that should be able to see each other and without a hitch.

Band

Selecting the band is a standard way to specify the protocol to be used by wireless interfaces. In addition to determining the standard protocol, the band also specify the data rates that can be missed, channel frequencies and channel widths. There are few bands in mikrotik router.

• 2GHz-b, working at a frequency of 2.4 GHz. Using 802.11b protocol with a maximum data rate of 11 Mbit / s.
• 2GHz-b / g, also works at a frequency of 2.4 GHz. Using 802.11b and 802.11g protocols. 802.11g protocol is almost the same as 802.11b but is transmitting with a base such as 802.11a OFDM 802.11g protocol that can reach 54 Mbit / s.
• 2Ghz-b/g/n, working at a frequency of 2.4 GHz. Using 802.11b, 802.11g and 802.11n. The development of the standard 802.11 protocol, coupled with the ability of multiple-input multiple-output (MIMO). With the addition of the MIMO feature, the maximum theoretically achievable data rate is 300 Mbit / s.
• 2GHz-only G, working at a frequency of 2.4 GHz, just use the 802.11g protocol.
• 2GHz-only N, working at a frequency of 2.4 GHz, just use the 802.11n protocol.
• 5GHz-a, working at a frequency of 5 GHz. Using the 802.11a protocol, the maximum data rate that can be achieved is 54 Mbit / s.
• 5GHz-a / n, working at a frequency of 5 GHz. Using 802.11a and 802.11n protocol.
• 5GHz-only N, working at a frequency of 5 GHz and only using 802.11n protocol.

If we look, there are several options that the band uses more than one protocol. If we set a wireless interface with a band that uses more than one protocol, then the wireless interfaces provide options to the client, where the protocols that support the client device.

Frequency

Wireless LAN uses a radio frequency propagation medium that also need to be clean and without interruption. Interference can be obstacles such as trees, buildings, walls, glass or frequency interference from other devices in the vicinity.

In order to form a good wireless link, this disorder should be avoided. The first thing to do is to do a site survey first to determine the physical condition of the field and the use of existing frequencies. For example, the presence of obstructions such as hills, buildings, trees, walls, glass, etc. should be avoided. We also need to know the frequency - a frequency that is around. its use will be avoided so that no interference / overlapping.

The allocation of frequencies is set in the regulations in each region and country. In Indonesia, for the purposes already dalokasikan wireless LANs in the ISM band at 2.4 GHz and 5.8 GHz. More details her, to 2.4 GHz is divided into several channels with each channel width - 22MHz respectively.

So also with the 5GHz. 5GHz frequency is also divided into several channels.

In the proxy, each channel is displayed with its midpoint frequency. For example in the 2.4 GHz band, channel1 = 2412, etc..

Back to the interference problem. In proxy there are several tools that can be used to perform the scanning frequency.

• Scanner Tool, double-click the wlan interface> set mode = station band and frequency> click scan.

• Snooper tool, double-click the wlan interface> set mode = station band and frequency> click snooper.

• Usage Frequency Tool, double-click the wlan interface> set mode = station band and frequency> click Freq. Usage

From these survey results, we can determine the frequency of use on our devices so as not to interfere with the other. Based on the distribution channel at 2.4 GHz, with a standard width of the channel, can be seen there are several mutually overlapping channels. This is what should be avoided so as not to interfere with each other and with well established wireless links. For example, the results of the scan turns out many are using the 2412 frequency (channel 1), then we can use the 2437 frequency (channel 6). Why not use 2417 (Ch.2) alone? not 2412 (Ch.1) and 2417 (Ch.2) are different.? Take a look at the image-sharing channel earlier, between 2412 (Ch.1) and 2417 (Ch.2) was still overlapping, mutually interfere. If pictured again, so as not to interfere with each other can use 2412 (Ch.1), 2437 (Ch. 6), 2462 (Ch. 11)

Well, if for freq 2484 (Ch.14) is a channel that is not standard. Devices like gadgets, laptops usually do not support.

Proxy support for 2484 (ch.14). But we still should not use these frequencies in vain. Although technically support devices, but the use of a clear allocation of frequencies outside violate the rules. So let's use the appropriate frequency of existing regulations. In order not to interfere with each other at other frequencies.

Tips for selection on the frequency of use of the 2.4 GHz band. How to 5GHz?. Most devices such as laptops, gadgets previously was only support for 2.4 GHz only. However, some gadgets now support 5GHz. Similarly to link wireless LAN devices today many are turning to 5GHz. In contrast to the distribution channel at 2.4 GHz, the distribution channel in the 5GHz no overlapping each other. To cover a laptop or gadget, can use the frequency 5725 - 5785 MHz. Most of today's gadgets support at these frequencies. Mikrotik product also has support for both 2.4 GHz and 5GHz bands. Support also for custom and custom channel width freq. But once again, the frequency of use wisely. Do not violate the regulation.

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Selection of Type of VPN

Selection of Type of VPN

 VPN is a method to build a network of links between network nodes in a safe / encrypted by using the public network (Internet / WAN). An example implementation is when you manage a network that consists of several offices in different locations. Would require substantial costs if we then establish a wireless link or fiber optic inter-office but could be located in the city or even a different island. With a VPN, we can establish a link between the office by utilizing the existing internet network. Links are formed secured with encryption to minimize the possibility of data will be accessible by people who are not responsible. Mikrotik VPN support several methods such as PPTP, L2TP, SSTP, and OpenVPN. Given some of these options, we need to select the type of VPN is suitable for our network. In general, all of these types have the same function. The difference is the authentication and encryption in use.

PPTP (Point to Point Tunnel Protocol)
PPTP VPN is one of the simplest type in the configuration. It is also flexible. The majority of operating systems already support the PPTP Client, both the operating system on a PC or gadgets like android. Communication PPTP uses TCP port 1723, and use the IP protocol for packet encapsulation 47/GRE data. In the PPTP settings, we can determine the network security protocol used to authenticate PPTP on Mikrotik, such as pap, chap, MSCHAP and mschap2. Then after the tunnel is formed, the transmitted data will be encrypted using Microsoft Point-to-Point Encryption (MPPE). Encryption process will usually make the transmitted packet header size will increase. If we are monitoring, traffick which passes through the PPTP tunnel will have overhead ± 7%.

L2TP (Layer 2 Tunnel Protocol)
L2TP is an extension of PPTP L2F plus. Network security and encryption protocol used to authenticate the same with PPTP. However, for communication, L2TP uses UDP port 1701. Usually for keamaanan better, combined with IPSec L2TP, L2TP/IPSec be. Examples for the Windows operating system, by default Windows OS using L2TP/IPSec. However, the consequences of course configuration that must be done is not that simple PPTP. The client side must already support IPSec when applying L2TP/IPSec. In terms of encryption, the encryption on L2TP/IPSec certainly have a higher level of security than PPTP uses MPPE reply. Traffick L2TP tunnel that passes overhead will have ± 12%.

SSTP (Secure Socket Tunneling Protocol)
To establish a method SSTP VPN with SSL certificates required in each device, unless both using RouterOS. SSTP communications using TCP port 443 (SSL), its the same thing as the website is secure (https). You have to make sure the clock is in conformity with the real time when using a certificate. Manyamakan time with real-time router can with NTP Client feature. Unfortunately not all OS Support VPN with SSTP method. Traffick SSTP tunnel that passes overhead will have ± 12%.

OpenVPN
VPN is usually used when needed on high data security. By default, OpenVPN uses UDP port 1194 and required certificate on each device to be connected. For compatibility client, OpenVPN can be built almost on all Operating Systems with the help of third-party applications. OpenVPN uses the sha1 and md5 algorithm for the authentication, and using some cipher that is blowfish128, AES128, AES192 and AES256. Traffic passing through the OpenVPN tunnel will have ± 16% overhead.

Keep in mind, that the more we need a secure network, the more complex configuration needs to be applied, as well as the use of hardware resources, the higher the encryption used, resource usage, especially CPU will also rise. The conclusion that we can take, if you want a VPN client that dg better device compatibility, then PPTP could be an option. In addition, PPTP can also be an option if you do not want too much trouble to do the configuration. But if you want a VPN with better security, use L2TP/IPsec or OpenVPN. Typically for windows OS, by default using L2TP/IPSec, so stay diseusuaikan on the server side. If your device supports it and you need a high security on the path that your VPN, L2TP/IPSec could be an option. One thing to note, the use of a VPN can not increase the bandwidth (more precisely reduce your bandwidth because there are additional headers), depending on the bandwidth of your subscription.

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Hard Work Sampaoli Praise Chile

Getty Images Sport / Matthias Hangst

Sao Paulo - The hard work of Chile to avoid defeat inviting praise from the coach, Jorge Sampaoli. La Roja proved itself with an aggressive appearance.

Chile lost 0-2 to the Netherlands in the match at the Arena Corinthians, Monday (23/06/2014) evening hrs. With this defeat, Arturo Vidal et al. had to settle for finishing as runners-up in Group B while group winners position achieved Der Oranje.

Despite losing, Chile appeared dominant in this game. Whoscored noting their superior ball possession 68% versus 32% belonged to the Dutch. Sampaoli also lamented his team failed to find a gap for at least an equalizer.

"Unfortunately we did not find a way to equalize. This is a game that is very narrowly in terms of trying to re-balance and make changes in the score., But we did not give up and the players gave great effort," said Espana Football Sampaoli quoted.

"The Dutch appear to wait and we are looking for an equalizer but the situation is very complicated. We want to finish on top, but now we have to think of Group A and who the next opponent," he added.

Qualify for the round of 16, Chile is now looking forward to the next opponent. As a group runner-up, they will face the winners of Group A, which is still contested by Brazil, Mexico, and Croatia.

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Why Saudi Arabia needs a new defense doctrine

By Nawaf Obaid, Special to CNN

Editor’s note: Nawaf Obaid is a fellow at the Belfer Center for Science and International Affairs at the Harvard Kennedy School, a senior fellow at the King Faisal Center for Research and Islamic Studies, and author of A Saudi Arabian Defense Doctrine. The views expressed are his own.
It’s hard to overstate the implications of the unfolding violence in Iraq for the prospects of stability in the Arab world. As tribal and Baathist opponents of Prime Minister Nuri al-Maliki’s regime have joined with the jihadis of the Islamic State of Iraq and Syria to seize major Sunni urban centers such as Mosul, the Iraqi army has simply melted away, consistently failing to offer even nominal resistance.
The problem for Iraq’s neighbors is that the current turmoil looks set to evolve into something even more destabilizing – a sectarian conflict and perhaps civil war that pits Sunnis against Shias. Indeed, the possibility of this only increased with al-Maliki’s apparent willingness to once again turn to Iran for support. But in his efforts to bolster his own Shia-led government, al-Maliki has stoked broader tensions in the Muslim world between the overwhelming majority Sunnis and minority Shias.
And Saudi Arabia is unlikely to sit idly by as all this unfolds.
Such instability has prompted genuine concern within Saudi Arabia, concern that has been compounded by signs that the United States and its European allies are undertaking a strategic re-evaluation of their willingness to commit military force to the Middle East. (Their hesitation is, of course, understandable given that the U.S. and others have lost no small number of lives and spent hundreds of billions of dollars trying to bring down tyrannical regimes in Iraq, Libya, and Afghanistan).
In addition, the Obama administration is also no doubt wary about sending its military to support a Shia regime lest it look like it is taking sides in a sectarian conflict, something that would have disastrous consequences for U.S. and European interests in the wider Sunni Arab world.
All this is happening at a time when Arabs have been starting to move on from their colonial past, one that burdened them with arbitrary national borders that are proving so complicated to maintain. And as the U.S. and European powers look to play a more hands-off role, Arab nations are discovering that they must learn to manage their own affairs, and begin the long postponed and difficult process of debating, assessing, and solving their own problems.
But while the anarchy that Arab nations find themselves surrounded by appears to have taken many by surprise, anyone following the region closely should have seen this coming. Indeed, as I noted in a studypublished by the Harvard Kennedy School in March 2013, Iraq is just one of a number of Arabstates in the region – along with Sudan, Yemen, Syria, Somalia, and Libya – that are either teetering on the edge of chaos, or have already fallen over.
With all this in mind, it is hardly surprising that Saudi Arabia – the Arab world's most powerful state – is rethinking its place in the Middle East, and how it can and should respond to what is going on around it. Saudi Arabia’s defense will clearly need to be a central part of that conversation. But what should a new and much-needed defense doctrine look like?There are four key points to consider over what a new Saudi surge will be based on.
Saudi Arabia’s size and economic strength mean it is in a unique position to lead an evolving Arab world, and it has been investing significantly in developing its military capacity to secure its northern and southern borders, as well as the surrounding sea-lanes that are so vital to both the global energy trade and the stability of the international financial system. Indeed, in 2013, Saudi Arabia passed the United Kingdom to become the world’s fourth-largest defense spender.
But while securing the Kingdom’s borders is of paramount importance, power projection is another essential capability for a nation, including the capacity to be able to fight two concurrent conflicts, if necessary, while still being able to defend the homeland. With the upheaval currently facing the region, such a scenario doesn’t seem particularly far-fetched, at least in the medium term.
Meanwhile, the advances by ISIS – an al Qaeda splinter group – are another reminder that a key element of any nation’s defense must be a counter-terrorism capability. After all, the militant “legions” that have seized Iraq’s second city among others are basically non-state actors. It is therefore essential that Saudi Arabia continue to invest in what is already one of the largest and most efficient counter-terrorism programs in the world to ensure that the threat is managed both within and outside the Kingdom’s borders.
Finally, central to any Saudi defense doctrine should be a commitment to bolstering its strategic partners – and there are encouraging signs the Kingdom is already aware and following through. For example, when Iran-supported insurgents sought to overthrow the government of Bahrain, the Saudis were quick to spearhead a Gulf Co-operation Council contingent that moved in to secure critical state infrastructure.Such moves are likely to increase in number, especially as the number of weak, failing or failed Arab states facing insurgencies continues to rise.
The reality is that as the Kingdom's northeastern neighbor teeters on the brink of total civil breakdown, the Saudis must prepare for the worst even as they know that they face myriad other challenges including civil war in Syria and Libya, Iran-backed revolutionary movements in the region, terrorist organizations and social disorder in Yemen and Afghanistan, and extremely tenuous political situations inPakistan, Egypt, Jordan,Lebanon, Tunisia and Bahrain.
True, the kind of defense doctrine outlined above needs to be flexible and able to adapt to constantly changing realities in the Middle East and the wider Muslim world. But if the Saudis can follow these broad principles, they should be well-placed to help ensure the Kingdom remains both a strong and secure nation state – and the central anchor of stability in the Arab world.

Post by: CNN's Jason Miks