Spanning-Tree Protocol is a link management protocol that provides path redundancy while preventing undesirable loops in the network. For an Ethernet network to function properly， only one active path can exist between two stations. Multiple active paths between stations cause loops in the network. If a loop exists in the network topology， the potential exists for duplication of messages. When loops occur， some switches see stations appear on both sides of the switch. This condition confuses the forwarding algorithm and allows duplicate frames to be forwarded. To provide path redundancy， Spanning-Tree Protocol defines a tree that spans all switches in an extended network. Spanning-Tree Protocol forces certain redundant data paths into a standby （blocked） state. If one network segment in the Spanning-Tree Protocol becomes unreachable， or if Spanning-Tree Protocol costs change， the spanning-tree algorithm reconfigures the spanning-tree topology and reestablishes the link by activating the standby path. Spanning-Tree Protocol operation is transparent to end stations， which are unaware whether they are connected to a single LAN segment or a switched LAN of multiple segments.There is a lab about STP in Cisco CCNP 642-812 / 642- 892 exam. Requirements: You will configure FastEthernet ports 0/12 through 0/24 for users who belong to VLAN 20. Also, all VLAN and VTP configurations are to be completed in global configuration mode as VLAN database mode is being deprecated by Cisco. You are required to accomplish the following tasks: 1. Ensure the switch does not participate in VTP but forwards VTP advertisements received on trunk ports. 2. Ensure all non-trunking interfaces (Fa0/1 to Fa0/24) transition immediately to the forwarding state of Spanning-Tree. 3. Ensure all FastEthernet interfaces are in a permanent non-trunking mode. 4. Place FastEthernet interfaces 0/12 through 0/24 in VLAN 20
“计价规范”中的工程量清单综合单价是一种狭义上的综合单价，在项目单价中不包括（）。 ["A.不能计量的措施项目 ","B.税金 ","C.计日工 ","D.总承包服务费 ","E.规费"]
全体股东的货币出资额不得低于注册资本的（） ["20%","25%","30%","35%"]
集料的相对密度.吸水率对沥青混合料的力学性能的影响是明显的，因此吸水率为（）的石料比较合适。 ["0.5%～1%","2%～3%","0.3%～0.7%","1%～1.5%"]
修订后的《条例》的规定，党员具有下列（）情形的，应当给予党纪处分。 ["违反议事规则，个人或者少数人决定重大问题的","利用职权或者职务上的影响，为本人配偶、子女及其配偶等亲属和其他特定关系人的经营活动谋取利益的","违反有关规定在经济实体、社会团体等单位中兼职，或者经批准兼职但获取薪酬、奖金、津贴等额外利益的","违反有关规定干预和插手建设工程项目承发包、招投标活动的"]
工作分析
