第3题: [简答题]what is the difference between the HSRP and VRRP？ 参考答案:
（1）VRRP is an IEEE standard （RFC 2338） for router redundancy； HSRP is a Cisco proprietary protocol.
（2）VRRP allows actual router IP address to be the same with the virtual IP，and if the same the router which get the IP will become Master router of the VRRP group；HSRP do not allow actual router IP address to be the same with the virtual IP.
（3）HSRP uses the multicast address 224.0.0.2 which represent all router in the subnet ， while VRRP uses the multicast address 224.0.0.18；HSRP uses UDP port 1985 while VRRP uses a protocol number of 112.
（4）HSRP may have one active router，one standby router，multiple listening router.While VRRP may have one master router，multiple backup router.
（5）HSRP exchange three kinds of message， hello message，coup message ，resign message. VRRP exchange only one kind of message， advertisement message.
（6）In VRRP，preempt is enable by default.But in HSRP preemt is disable by default.
第4题: [单项选择]骨肿瘤的临床表现和诊断下列哪项最为正确 A. 疼痛是恶性肿瘤的特征性症状 B. 转移性骨肿瘤X线片上均是溶骨性破坏 C. 骨肿瘤的诊断绝对依靠病理检查 D. 碱性磷酸酶下降可排除恶性肿瘤的可能 E. Codman’s三角常见于骨肉瘤 参考答案:E
