ASR1k OTV的三个时间戳
23 12 月, 2014,由 frank撰写
1. ARP的老化时间
OTV有ARP suppress feature – ARP ND Cache，它只会允许通过第一个ARP，并记在缓存中，后续的到同样地址的ARP会被阻止，由OTV设备代理回复，这个时间是600s，10分钟，用”show otv detail“可以查看，这个时间不能更改，但可以关闭！在一些特殊的环境中可能需要！
ASR1004-1#sh otv de | i ARP ARP Suppression Enabled : Yes ARP Cache Timeout : 600 seconds ASR1004-1# ASR1004-1#sh otv arp-nd-cache Overlay0 ARP/ND L3->L2 Address Mapping Cache BD MAC Layer-3 Address Age (HH:MM:SS) Local/Remote 16 1c1d.8646.5ec4 21.21.21.253 00:00:04 Remote ASR1004-1(config)#int overlay 0 ASR1004-1(config-if)#no otv suppress arp-nd ?
2. MAC地址的老化时间
在常规网络设备上，MAC的老化时间默认都是5分钟
而在OTV设备上，MAC的老化时间是30分钟，通过下面命令查看，并且可以更改，但注意我们ASR1k的OTV不支持静态绑定MAC，已经确认，N7k可以支持
ASR1004-1#sh bridge-domain 16 Bridge-domain 16 (2 ports in all) State: UP Mac learning: Enabled Aging-Timer: 1800 second(s) GigabitEthernet0/0/1 service instance 16 Overlay0 service instance 16 AED MAC address Policy Tag Age Pseudoport 1 FFFF.FFFF.FFFF flood static 0 OLIST_PTR:0x92d6c0b0 1 1C1D.8646.5EC4 forward static_r 0 OCE_PTR:0x8cc51c00 >>> 从远端OTV传过来的MAC 1 001D.A220.154B forward dynamic_c 1793 GigabitEthernet0/0/1.EFP16 >>> 从l2口上学到的MAC SR1004-1(config)#bridge-domain 16 ASR1004-1(config-bdomain)#mac ? aging-time Set age time of mac addresses per bridge domain learning Disable mac learning on bridge domain limit Limit the MAC Addresses learnt
3. ISIS 路由延迟优化时间
咱们的OTV是通过扩展ISIS的TLV去传送MAC的，所以可以通过查看数据库来看MAC地址信息，注意要跟全局的ISIS区分开。另外当你远端的OTV设备把地址清掉后，本端不会立即从ISIS 中清掉这个LSP，它会delay 10分钟，此值不能更改。在这10分钟内完成流量的迁移，如AED的选举等，这样保证了流量不会丢掉，由于OTV设备只作为WAN的通道，所以即使有10分钟延时也不会有什么影响，因为控制流量是否到OTV设备，取决于下面交换机的行为。这个延迟可以通过ISIS查看
下面是基本OTV isis的信息：
ASR1004-1#show otv isis ?
Overlay Overlay interface
aed Authoritative Edge Device
database ISIS database information
hostname IS-IS Dynamic hostname mapping
local Local node
lsp-log IS-IS LSP log
neighbors IS-IS neighbors
nsf Non-stop forwarding state
protocol IS-IS protocol details
remote Remote node
rib ISIS local RIB information
site IS-IS L2 Site process
site-index ISIS site index information
spf-log IS-IS SPF log
vlan ISIS VLAN information
vlan-database ISIS VLAN database information
ASR1004-1#show otv isis database
Tag Overlay0:
IS-IS Level-1 Link State Database:
LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OL
ASR1004-2.00-00 0x000000DC 0xCDD7 1189 0/0/0
ASR1004-1.00-00 * 0x000000F4 0xEE7A 1014 0/0/0
ASR1004-1.01-00 * 0x000000C4 0x145F 411 0/0/0
ASR1004-1#
ASR1004-1#show otv isis database ASR1004-2.00-00 de
Tag Overlay0:
IS-IS Level-1 LSP ASR1004-2.00-00
LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OL
ASR1004-2.00-00 0x000000DC 0xCDD7 1178 0/0/0
Area Address: 00
NLPID: 0xCC 0x8E
Hostname: ASR1004-2
Metric: 10 IS-Extended ASR1004-1.01
ED Summary:
Site ID: 0000.0000.0002 >>> 对端的site id配置”otv site-identifier 0000.0000.0002“
AED-Server-ID: F8C2.88C6.4F00
Version: 22
Device ID: F8C2.88C6.4F00, fwd_ready: 1 >>> 对端WAN口的MAC地址
VLAN Status:
Site ID: 0000.0000.0002 Partition ID: FFFF.FFFF.FFFF
Device ID: F8C2.88C6.4F00 Cluster-ID: 0
AED: 1 Back-up AED: 0 Fwd ready: 1 Priority 0
Delete: 0 Local: 1 Remote: 1 Range: 1 Version 1
Start-vlan:16 End-vlan: 16 Step: 1
AED Server:
Site ID: 0000.0000.0002 Partition ID: FFFF.FFFF.FFFF
Device ID: F8C2.88C6.4F00 Cluster-ID: 0
Old-AED: 0000.0000.0000 New-AED: F8C2.88C6.4F00
Old-Backup-AED: 0000.0000.0000 New-Backup-AED: 0000.0000.0000
Delete: 0 Range: 1 Version 1
Start-vlan:16 End-vlan: 16 Step: 1
Layer 2 MAC Reachability: topoid 0, vlan 16, confidence 1
1c1d.8646.5ec4 >>> 传递的客户的MAC地址
下面是对端清掉后，本端会立即激活这个计时器：
ASR1004-2#show otv isis rib mac
Tag Overlay0:
MAC local rib for Overlay0 (Total 1)
L2 Topology ID Mac Address
16 5475.D03C.8821
[50/1] via 188.100.251.1(Overlay0), LSP[0/0], site-index 1, aged out 00:00:10 ago