Hey to all. Since around 2 months, I am with 99bitcoins reading and getting info and I am very happy here, thanks for a good site. For my bad luck I did not check here for a review of coinbase, I would have save a lot of worthless time. To tell the truth, I hope there is a internet god out there and shut them down. I did not know about their support in US, but as I read the first reviews here, it seems they make themselves a pretty bad place there too. I am located in the D.R.,… Read more »


Bitcoin is the world’s first virtual digital currency underpinned by a completely decentralized blockchain technology also known as the Distributed Ledger Technology (DLT). Bitcoin was first created in 2009 by an anonymous identity of Satoshi Nakamoto. Bitcoin allows for peer-to-peer transactions and is completely free of any third-party involvement like financial institutions or central banks. The Bitcoin’s blockchain network maintains a history of all the transactions made and facilitates instant funds transfer with minimal transaction fees required to cover the cost of network operation. The total supply of Bitcoin is fixed at 21 million coins and its smallest fractional unit is called as Satoshi. Each Satoshi is a hundred millionth of a Bitcoin which means 100,000,000 Santoshi = 1 BTC. Bitcoins are generated by a process known as ‘mining’ which involves solving of complex mathematical algorithms. The miners involved in the mining process look after the Bitcoin network security and validate each transactions taking place on the network. Bitcoin can be exchanged with other digital currencies or fiat currencies. Bitcoin is used as a means of payment by over 100,000 vendors and merchants.


I have not been using Coinbase long but I have used it long enough to feel like I’m getting burned. I am using Coinbase as, what I call, a pass through as in the end, I am purchasing crypto that is not supported by Coinbase with the BTC I purchase through Coinbase. While the app itself is great as it is easy to navigate the process of withdrawing funds is not so great. I purchased BTC with the intent of withdrawing to purchase another crypto. A week and several emails later my BTC has not yet been released for withdraw. Prior to this transaction I had done several others successfully with no issues, now, for no reason whatsoever my funds are pended for “further research”. I am a patient person but as I’m sitting here waiting the BTC value is falling and the cost of the crypto I am looking to purchase is rising which means at this point I have missed out on a few hundred dollars of profit all because Coinbase won’t release my funds. I am giving only 1 star because (1) communication with Customer Service has not been great as I am still sitting here clueless on what’s going on and (2) I’ve missed out on significant profit and have no idea why or have any sense of comfort that this won’t be an ongoing issue
从广义上来看,网络交换机分为两种:广域网交换机和局域网交换机。广域网交换机主要应用于电信领域,提供通信用的基础平台。而局域网交换机则应用于局域网络,用于连接终端设备,如PC机及网络打印机等。从传输介质和传输速度上可分为以太网交换机、快速以太网交换机、千兆以太网交换机、FDDI交换机、ATM交换机和令牌环交换机等。从规模应用上又可分为企业级交换机、部门级交换机和工作组交换机等。各厂商划分的尺度并不是完全一致的,一般来讲,企业级交换机都是机架式,部门级交换机可以是机架式(插槽数较少),也可以是固定配置式,而工作组级交换机为固定配置式(功能较为简单)。另一方面,从应用的规模来看,作为骨干交换机时,支持500个信息点以上大型企业应用的交换机为企业级交换机,支持300个信息点以下中型企业的交换机为部门级交换机,而支持100个信息点以内的交换机为工作组级交换机。 [3] 




If you want to trade in digital currencies, you are going to need a platform on which to trade them, and an intermediary to communicate with the network. Coinbase is a global digital asset exchange company (GDAX), providing a venue to buy and sell digital currencies, as well as send information about those transactions out to the blockchain network to verify those transactions. Coinbase serves as a wallet, too, where the digital currencies can be stored. The application operates exchanges of Bitcoin, Ethereum, Bitcoin Cash, and Litecoin, as well as other digital assets with fiat currencies in 32 countries, and Bitcoin transactions in many more countries. According to its website, Coinbase has served over 10 million customers and facilitated the exchange of more than $50 billion worth of digital currency.


If you do have this much money tied up in Bitcoin, though, you may want a more secure space to store it. If this is the case, Coinbase offers a Coinbase vault, which has time-delayed withdrawals (giving you 48 hours to cancel a withdrawal) and the option of multiple approvers, increasing security by ensuring that all withdrawals are approved by multiple people. They also offer a multisig vault, which is basically an even more involved and more secure vault, requiring multiple keys to unlock. 


         3. 性能体现不一样 从技术上讲,路由器和三层交换机在数据包交换操作上存在着明显区别。路由器一般由基于微处理器的软件路由引擎执行数据包交换,而三层交换机通过硬件执行数据包交换。三层交换机在对第一个数据流进行路由后,它将会产生一个MAC地址与IP地址的映射表,当同样的数据流再次通过时,将根据此表直接从二层通过而不是再次路由,从而消除了路由器进行路由选择而造成网络的延迟,提高了数据包转发的效率。同时,三层交换机的路由查找是针对数据流的,它利用缓存技术,很容易利用ASIC技术来实现,因此,可以大大节约成本,并实现快速转发。而路由器的转发采用最长匹配的方式,实现复杂,通常使用软件来实现,转发效率较低。 正因如此,从整体性能上比较的话,三层交换机的性能要远优于路由器,非常适用于数据交换频繁的局域网中;而路由器虽然路由功能非常强大,但它的数据包转发效率远低于三层交换机,更适合于数据交换不是很频繁的不同类型网络的互联,如局域网与互联网的互联。如果把路由器,特别是高档路由器用于局域网中,则在相当大程度上是一种浪费(就其强大的路由功能而言),而且还不能很好地满足局域网通信性能需求,影响子网间的正常通信。
On February 16, 2018, Coinbase admitted that some customers were overcharged in error for credit and debit purchases of cryptocurrencies. The problem was initiated when banks and card issuers changed the merchant category code (MCC) for cryptocurrency purchases earlier this month. This meant that cryptocurrency payments would now be processed as "cash advances", meaning that banks and credit card issuers could begin charging customers cash-advance fees for cryptocurrency purchases. Any customers who purchased cryptocurrency on their exchange between January 22 and February 11, 2018 could have been affected. At first, Visa blamed Coinbase, telling the Financial Times on February 16 that it had "not made any systems changes that would result in the duplicate transactions cardholders are reporting." However, the latest statement from Visa and Worldpay on the Coinbase blog clarifies: "This issue was not caused by Coinbase."[45]


Over 98% of cryptocurrency is stored securely offline and the rest is protected by industry-leading online security. Your account is also subject to the same scrupulous safety standards, including multi-stage verification and bank-level security. You can even lock the app with a passcode, or remotely disable your phone’s access to the app if it gets lost or stolen.