Vlans
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This document discusses VLANs (virtual local area networks) in Red Hat Enterprise Linux. It provides an overview of how VLANs work, splitting a single physical LAN into multiple logical LANs. Key points covered include how VLANs add tags to Ethernet frames to associate them with a VLAN, the different types of network ports (access and trunk), and how VLAN interfaces can be configured in RHEL using commands like vconfig. Examples are given of using VLANs to separate network traffic for different applications or virtual machines on a hypervisor.
Vlans
- 1. VLANs in Red Hat Enterprise Linux Raghu Udiyar Technical support engineer Red Hat 1 VLANs & you | Raghu Udiyar
- 2. First, LAN? ● Local Area Network ● Uses Ethernet for Layer 2 communication ● using MAC addresses ● ARP is used for IP -> MAC ● ARP uses broadcast ● LAN = 1 Broadcast domain ● A short refresher on how this works 2 VLANs & you | Raghu Udiyar
- 3. Port 1 A : f3:a3:34: Port 2 B : f2:de:34: This mac is D Port 3 C : f1:d1:23 On port 4 Port 4 D : f3:a4:56 Who is 192.x.x.x Hey, that's me Mac is f3:a4:x:x:x 3 VLANs & you | Raghu Udiyar
- 4. To recap ● A–B–C–D ● A -> D ● ARP broadcast, D is IP 192.x.x.x what is MAC? ● D replies with MAC ● A sends to switch ● Switch looks up the address in the MAC table ● Switch sends to D 4 VLANs & you | Raghu Udiyar
- 5. Any questions? 5 VLANs & you | Raghu Udiyar
- 6. VLANs ● Splits a LAN into multiple LANs ● Into multiple broadcast domains ● Splits single switch into multiple switches 6 VLANs & you | Raghu Udiyar
- 7. Port 1 A : f3:a3:34: Port 2 B : f2:de:34: Port 3 C : f1:d1:23 Port 4 D : f3:a4:56 B Trunk B B B B 7 VLANs & you | Raghu Udiyar
- 8. VLAN - Advantages ● Flexibility - No physical restrictions ● Security – layer 2 separation ● Cost effective ● Reduce size of broadcast domains 8 VLANs & you | Raghu Udiyar
- 9. How does this work? ● 802.1q protocol ● VLAN “Tags” VLAN ID Ethernet Frame ● VLAN 50, 100, etc (1 – 4094) 9 VLANs & you | Raghu Udiyar
- 10. Type of Ports ● Access port SW Ethernet PC1 Vid Ethernet Vlan id is stripped Ethernet PC2 Vid Ethernet SW 10 VLANs & you | Raghu Udiyar
- 11. Type of Ports ● Trunk Ports v Et SW SW v Et v Et Trunk Ports Carries all VLAN's 11 VLANs & you | Raghu Udiyar
- 12. Native Vlan v Et SW Et SW v Et v Et v Et Native Vlan Ethernet frame with no Vlan id get's the native VLAN 12 VLANs & you | Raghu Udiyar
- 13. Any questions? 13 VLANs & you | Raghu Udiyar
- 14. Vlans in RHEL ● Access ● Trunk ● Vlan interface : RHEL eth0.40 eth0.100 eth0.40 eth0.100 eth0.8 eth0.8 eth0 native vlan 14 VLANs & you | Raghu Udiyar
- 15. Use case 1 : SW1 Httpd Payroll eth0.40 eth0 SW2 15 VLANs & you | Raghu Udiyar
- 16. Use Case 2 : Hypervisor with two guests VM1 VM2 VLAN10 VLAN20 eth0 Trunk 16 VLANs & you | Raghu Udiyar
- 17. Demo - Assigning a Vlan ID ● # vconfig add eth0 7 ● # ip addr add dev eth0.7 192.168.0.1/24 brd + ● # ip link set dev eth0.7 up 17 VLANs & you | Raghu Udiyar
- 18. Troubleshooting ● Misconfiguration ● Check switch ● Misunderstanding of concepts ● Access/Trunk ● Native Vlan 18 VLANs & you | Raghu Udiyar
- 19. Any questions? 19 VLANs & you | Raghu Udiyar
- 20. Thank You