vrrp网关终端dhcp获取地址速度慢
问题描述
问题描述:
问题描述及现网拓扑如下图:
拓扑:
问题情况回溯:
1、客户需求:
在某企业网项目中,客户终端有有线业务、无线业务和IP电话业务。客户要求加入加入交换机做二层网络,并通过dhcp获取地址,并添加dhcp snooping保护dhcp服务器,防止内部dhcp服务器攻击。
2、问题回溯:
两台S7710交换机工作在三层作为网关设备,通过vrrp做双上联网关冗余,S5720设备作为接入连接在终端设备和AP设备上做二层通信,AC旁挂在核心设备上,使用直接转发模式,dhcp网关部署在核心交换机,AP网关部署在AC上。
客户使用dhcp获取地址,发现早晨员工获取地址速度有的人快有的人慢,部分间隔长达3-5分钟左右,但是获取到地址后并不影响使用。
处理过程
处理过程:
1、检查交换机接口配置是否正确,经过确认没有存在vlan划分错误问题,且交换机上联口开启了dhcp snooping trust。
2、检查dhcp地址池分配情况,发现地址池范围较为充足。
3、确认发现下联接入交换机有接口错包,且较为频繁。
4、确认发现vrrp存在切换。
根因
根因:
因客户核心网关配置为vrrp,且主备都存在dhcp服务器,但是核心交换机不存在dhcp心跳功能,无法同步dhcp分配信息,所以当网关发生切换将导致新用户获取dhcp地址时将需要针对所有已分配的地址进行冲突探测检查,当dhcp用户较多时就会导致dhcp获取速度缓慢。
解决方案
解决方案:
推荐将核心部署为堆叠或者调整冲突探测次数和时间。
调整dhcp冲突探测时间和次数命令:
system-view [sysname] dhcp server ping packet number 缺省情况下,设备分配IP地址时的冲突探测的次数为2 [sysname] dhcp server ping timeout milliseconds [sysname] duplex full 缺省情况下,设备分配IP地址时每次冲突探测的最长等待时间为500毫秒 堆叠配置命令:
system-view
[HUAWEI] sysname SwitchA
[SwitchA] interface stack-port 0/1
[SwitchA-stack-port0/1] port interface gigabitethernet 0/0/27 enable
Warning: Enabling stack function may cause configuration loss on the interface. Continue? [Y/N]:y
Info: This operation may take a few seconds. Please wait.
[SwitchA-stack-port0/1] quit
[SwitchA] interface stack-port 0/2
[SwitchA-stack-port0/2] port interface gigabitethernet 0/0/28 enable
Warning: Enabling stack function may cause configuration loss on the interface. Continue? [Y/N]:y
Info: This operation may take a few seconds. Please wait.
[SwitchA-stack-port0/2] quit
system-view
[HUAWEI] sysname SwitchB
[SwitchB] interface stack-port 0/1
[SwitchB-stack-port0/1] port interface gigabitethernet 0/0/27 enable
Warning: Enabling stack function may cause configuration loss on the interface. Continue? [Y/N]:y
Info: This operation may take a few seconds. Please wait.
[SwitchB-stack-port0/1] quit
[SwitchB] interface stack-port 0/2
[SwitchB-stack-port0/2] port interface gigabitethernet 0/0/28 enable
Warning: Enabling stack function may cause configuration loss on the interface. Continue? [Y/N]:y
Info: This operation may take a few seconds. Please wait.
[SwitchB-stack-port0/2] quit
[SwitchA] stack slot 0 priority 200
Warning: Please do not frequently modify Priority because it will make the stack split. Continue? [Y/N]:y
[SwitchB] stack slot 0 renumber 1
Warning: All the configurations related to the slot ID will be lost after the slot ID is modified.
Please do not frequently modify slot ID because it will make the stack split. Continue? [Y/N]:y
Info: Stack configuration has been changed, and the device needs to restart to make the configuration effective.
建议与总结
建议与总结:
当存在dhcp的场景下网关推荐使用堆叠部署。
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作者:SE_Gao
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来源:CNESA
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