CCNA LEARING NOTES---season 1---Internetworking
Remember the possible causes of LAN traffic congestion.
Too many hosts in a broadcast domain, broadcast storms, multicasting, and low bandwidth are all possible causes of LAN traffic congestion.
记住导致
LAN
拥塞的可能原因
:
在广播域中有太多的主机,广播风暴,组播和低带宽,是导致LAN拥塞的所有可能原因
Understand the difference between a collision domain and a broadcast domain.
Collision domain is an Ethernet term used to describe a network collection of devices in which one particular
device sends a packet on a network segment, forcing every other device on that same
segment to pay attention to it. On a broadcast domain, a set of all devices on a network segment
hear all broadcasts sent on that segment.
理解冲突与和广播域的区别.
冲突域是以太网术语,用来描述一个特定设备在网段上发送数据包时的网络场景,它迫使在同一网段上的其它所有设备都注意到它所发送的数据包.广播域是指一个网段上所有设备的集合,这些设备监听送往那个网段的所有广播.
Understand the difference between a hub, a bridge, a switch, and a router.
Hubs create one collision domain and one broadcast domain. Bridges break up collision domains but create one large broadcast domain. They use hardware addresses to filter the network. Switches are really just multiple port bridges with more intelligence. They break up collision domains but create one large broadcast domain by default. Switches use hardware addresses to filter the network. Routers break up broadcast domains (and collision domains) and use logical addressing to filter the network.
理解集线器
,
网桥
,
交换机和路由器之间的区别
.
集线器创建一个冲突域和一个广播域.网桥分割冲突域,但创建了一个大的广播域.它们使用硬件地址对网络进行过滤.交换机实际上只是智能化的 多端口网桥,他们分割冲突域,但默认是创建一个大的广播域.交换机使用硬件地址对网络进行过滤.路由器分隔广播域,并使用逻辑寻址对网络进行过滤.
Remember the difference between connection-oriented and connectionless network services.
Connection-oriented services use acknowledgments and flow control to create a reliable session.
More overhead is used than in a connectionless network service. Connectionless services are
used to send data with no acknowledgments or flow control. This is considered unreliable.
记住面向连接的网络服务和无连接的网络服务之间的区别
.
面向连接的服务使用确认技术和流量控制,以建立可靠的会话连接.在面向连接的网络服务中,增加了更多的管理开销.无连接的服务用来传送不带确认或流量控制的数据,它被认为是不可靠的.
Remember the OSI layers.
You must remember the seven layers of the OSI model and what function each layer provides. The Application, Presentation, and Session layers are upper layers and are responsible for communicating from a user interface to an application. The Transport layer provides segmentation, sequencing, and virtual circuits. The Network layer provides logical network addressing and routing through an internetwork. The Data Link layer provides framing and placing of data on the network medium. The Physical layer is responsible for taking 1s and 0s and encoding them into a digital signal for transmission on the network segment.
记住
OSI
模型中的各层
.
必须记住OSI模型中的7个层次,以及每一层所提供的功能.应用层,表示层和会话层是高层,它们负责从用户接口到应用程序的通信.传输层负 责提供分段,排序和虚电路.网络层提供逻辑网络寻址功能,并通过互联网络进行路由选择.数据链路层将数据封装成帧,并将数据送到网络介质上.物理层负责接 收1,0代码,并将它们编码为数字信号,以便在网段上传输.
Remember the types of Ethernet cabling and when you would use them.
The three types of cables that can be created from an Ethernet cable are straight-through (to connect a PC’s or a router’s Ethernet interface to a hub or switch), crossover (to connect hub to hub, hub to switch, switch to switch, or PC to PC), and rolled (for a console connection from a PC to a router or switch).
记住以太网电缆的类型
,
以及何时使用这些电缆类型
.
用于组建以太网的电缆有3种:直通电缆(用来将PC或路由器的以太网接口连接到集线器或交换机上),交叉电缆(用来实现集线器到集线器,集线器到交换机,交换机到交换机或PC到PC的连接),反转电缆(用于PC到交换机或路由器控制台的连接)
Remember the three layers in the Cisco three-layer model. The three layers in the Cisco
hierarchical model are the core, distribution, and access layers.
记住
CISCO 3
层模型中的
3
个层次.
CISCO层次模型中的3个层次为: 核心层,分配层和接入层.
单词:
segment 分段 ; data stream 数据段 ; encapsulate 封装 ; full-duplex 全双工 ; EMI 电磁 ; flow control 流量控制 ; buffering 缓冲 ; Windowing 窗口机制 ; Congestion 拥塞 ; govern 控制 ; binary 二进制 ; decimal 十进制 ; hexadecimal 十六进制